This is libc.info, produced by makeinfo version 5.2 from libc.texinfo.

This file documents the GNU C Library.

   This is ‘The GNU C Library Reference Manual’, for version 2.25.

   Copyright © 1993–2017 Free Software Foundation, Inc.

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being “Free Software Needs Free Documentation” and
“GNU Lesser General Public License”, the Front-Cover texts being “A GNU
Manual”, and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled "GNU Free Documentation
License".

   (a) The FSF’s Back-Cover Text is: “You have the freedom to copy and
modify this GNU manual.  Buying copies from the FSF supports it in
developing GNU and promoting software freedom.”
INFO-DIR-SECTION Software libraries
START-INFO-DIR-ENTRY
* Libc: (libc).                 C library.
END-INFO-DIR-ENTRY

INFO-DIR-SECTION GNU C library functions and macros
START-INFO-DIR-ENTRY
* a64l: (libc)Encode Binary Data.
* abort: (libc)Aborting a Program.
* abs: (libc)Absolute Value.
* accept: (libc)Accepting Connections.
* access: (libc)Testing File Access.
* acosf: (libc)Inverse Trig Functions.
* acoshf: (libc)Hyperbolic Functions.
* acosh: (libc)Hyperbolic Functions.
* acoshl: (libc)Hyperbolic Functions.
* acos: (libc)Inverse Trig Functions.
* acosl: (libc)Inverse Trig Functions.
* addmntent: (libc)mtab.
* addseverity: (libc)Adding Severity Classes.
* adjtime: (libc)High-Resolution Calendar.
* adjtimex: (libc)High-Resolution Calendar.
* aio_cancel64: (libc)Cancel AIO Operations.
* aio_cancel: (libc)Cancel AIO Operations.
* aio_error64: (libc)Status of AIO Operations.
* aio_error: (libc)Status of AIO Operations.
* aio_fsync64: (libc)Synchronizing AIO Operations.
* aio_fsync: (libc)Synchronizing AIO Operations.
* aio_init: (libc)Configuration of AIO.
* aio_read64: (libc)Asynchronous Reads/Writes.
* aio_read: (libc)Asynchronous Reads/Writes.
* aio_return64: (libc)Status of AIO Operations.
* aio_return: (libc)Status of AIO Operations.
* aio_suspend64: (libc)Synchronizing AIO Operations.
* aio_suspend: (libc)Synchronizing AIO Operations.
* aio_write64: (libc)Asynchronous Reads/Writes.
* aio_write: (libc)Asynchronous Reads/Writes.
* alarm: (libc)Setting an Alarm.
* aligned_alloc: (libc)Aligned Memory Blocks.
* alloca: (libc)Variable Size Automatic.
* alphasort64: (libc)Scanning Directory Content.
* alphasort: (libc)Scanning Directory Content.
* ALTWERASE: (libc)Local Modes.
* ARG_MAX: (libc)General Limits.
* argp_error: (libc)Argp Helper Functions.
* ARGP_ERR_UNKNOWN: (libc)Argp Parser Functions.
* argp_failure: (libc)Argp Helper Functions.
* argp_help: (libc)Argp Help.
* argp_parse: (libc)Argp.
* argp_state_help: (libc)Argp Helper Functions.
* argp_usage: (libc)Argp Helper Functions.
* argz_add: (libc)Argz Functions.
* argz_add_sep: (libc)Argz Functions.
* argz_append: (libc)Argz Functions.
* argz_count: (libc)Argz Functions.
* argz_create: (libc)Argz Functions.
* argz_create_sep: (libc)Argz Functions.
* argz_delete: (libc)Argz Functions.
* argz_extract: (libc)Argz Functions.
* argz_insert: (libc)Argz Functions.
* argz_next: (libc)Argz Functions.
* argz_replace: (libc)Argz Functions.
* argz_stringify: (libc)Argz Functions.
* asctime: (libc)Formatting Calendar Time.
* asctime_r: (libc)Formatting Calendar Time.
* asinf: (libc)Inverse Trig Functions.
* asinhf: (libc)Hyperbolic Functions.
* asinh: (libc)Hyperbolic Functions.
* asinhl: (libc)Hyperbolic Functions.
* asin: (libc)Inverse Trig Functions.
* asinl: (libc)Inverse Trig Functions.
* asprintf: (libc)Dynamic Output.
* assert: (libc)Consistency Checking.
* assert_perror: (libc)Consistency Checking.
* atan2f: (libc)Inverse Trig Functions.
* atan2: (libc)Inverse Trig Functions.
* atan2l: (libc)Inverse Trig Functions.
* atanf: (libc)Inverse Trig Functions.
* atanhf: (libc)Hyperbolic Functions.
* atanh: (libc)Hyperbolic Functions.
* atanhl: (libc)Hyperbolic Functions.
* atan: (libc)Inverse Trig Functions.
* atanl: (libc)Inverse Trig Functions.
* atexit: (libc)Cleanups on Exit.
* atof: (libc)Parsing of Floats.
* atoi: (libc)Parsing of Integers.
* atol: (libc)Parsing of Integers.
* atoll: (libc)Parsing of Integers.
* backtrace: (libc)Backtraces.
* backtrace_symbols_fd: (libc)Backtraces.
* backtrace_symbols: (libc)Backtraces.
* basename: (libc)Finding Tokens in a String.
* basename: (libc)Finding Tokens in a String.
* BC_BASE_MAX: (libc)Utility Limits.
* BC_DIM_MAX: (libc)Utility Limits.
* bcmp: (libc)String/Array Comparison.
* bcopy: (libc)Copying Strings and Arrays.
* BC_SCALE_MAX: (libc)Utility Limits.
* BC_STRING_MAX: (libc)Utility Limits.
* bind: (libc)Setting Address.
* bind_textdomain_codeset: (libc)Charset conversion in gettext.
* bindtextdomain: (libc)Locating gettext catalog.
* BRKINT: (libc)Input Modes.
* brk: (libc)Resizing the Data Segment.
* bsearch: (libc)Array Search Function.
* btowc: (libc)Converting a Character.
* BUFSIZ: (libc)Controlling Buffering.
* bzero: (libc)Copying Strings and Arrays.
* cabsf: (libc)Absolute Value.
* cabs: (libc)Absolute Value.
* cabsl: (libc)Absolute Value.
* cacosf: (libc)Inverse Trig Functions.
* cacoshf: (libc)Hyperbolic Functions.
* cacosh: (libc)Hyperbolic Functions.
* cacoshl: (libc)Hyperbolic Functions.
* cacos: (libc)Inverse Trig Functions.
* cacosl: (libc)Inverse Trig Functions.
* calloc: (libc)Allocating Cleared Space.
* canonicalize_file_name: (libc)Symbolic Links.
* canonicalizef: (libc)FP Bit Twiddling.
* canonicalize: (libc)FP Bit Twiddling.
* canonicalizel: (libc)FP Bit Twiddling.
* cargf: (libc)Operations on Complex.
* carg: (libc)Operations on Complex.
* cargl: (libc)Operations on Complex.
* casinf: (libc)Inverse Trig Functions.
* casinhf: (libc)Hyperbolic Functions.
* casinh: (libc)Hyperbolic Functions.
* casinhl: (libc)Hyperbolic Functions.
* casin: (libc)Inverse Trig Functions.
* casinl: (libc)Inverse Trig Functions.
* catanf: (libc)Inverse Trig Functions.
* catanhf: (libc)Hyperbolic Functions.
* catanh: (libc)Hyperbolic Functions.
* catanhl: (libc)Hyperbolic Functions.
* catan: (libc)Inverse Trig Functions.
* catanl: (libc)Inverse Trig Functions.
* catclose: (libc)The catgets Functions.
* catgets: (libc)The catgets Functions.
* catopen: (libc)The catgets Functions.
* cbc_crypt: (libc)DES Encryption.
* cbrtf: (libc)Exponents and Logarithms.
* cbrt: (libc)Exponents and Logarithms.
* cbrtl: (libc)Exponents and Logarithms.
* ccosf: (libc)Trig Functions.
* ccoshf: (libc)Hyperbolic Functions.
* ccosh: (libc)Hyperbolic Functions.
* ccoshl: (libc)Hyperbolic Functions.
* ccos: (libc)Trig Functions.
* ccosl: (libc)Trig Functions.
* CCTS_OFLOW: (libc)Control Modes.
* ceilf: (libc)Rounding Functions.
* ceil: (libc)Rounding Functions.
* ceill: (libc)Rounding Functions.
* cexpf: (libc)Exponents and Logarithms.
* cexp: (libc)Exponents and Logarithms.
* cexpl: (libc)Exponents and Logarithms.
* cfgetispeed: (libc)Line Speed.
* cfgetospeed: (libc)Line Speed.
* cfmakeraw: (libc)Noncanonical Input.
* cfree: (libc)Freeing after Malloc.
* cfsetispeed: (libc)Line Speed.
* cfsetospeed: (libc)Line Speed.
* cfsetspeed: (libc)Line Speed.
* chdir: (libc)Working Directory.
* CHILD_MAX: (libc)General Limits.
* chmod: (libc)Setting Permissions.
* chown: (libc)File Owner.
* CIGNORE: (libc)Control Modes.
* cimagf: (libc)Operations on Complex.
* cimag: (libc)Operations on Complex.
* cimagl: (libc)Operations on Complex.
* clearenv: (libc)Environment Access.
* clearerr: (libc)Error Recovery.
* clearerr_unlocked: (libc)Error Recovery.
* CLK_TCK: (libc)Processor Time.
* CLOCAL: (libc)Control Modes.
* clock: (libc)CPU Time.
* CLOCKS_PER_SEC: (libc)CPU Time.
* clog10f: (libc)Exponents and Logarithms.
* clog10: (libc)Exponents and Logarithms.
* clog10l: (libc)Exponents and Logarithms.
* clogf: (libc)Exponents and Logarithms.
* clog: (libc)Exponents and Logarithms.
* clogl: (libc)Exponents and Logarithms.
* closedir: (libc)Reading/Closing Directory.
* close: (libc)Opening and Closing Files.
* closelog: (libc)closelog.
* COLL_WEIGHTS_MAX: (libc)Utility Limits.
* _Complex_I: (libc)Complex Numbers.
* confstr: (libc)String Parameters.
* conjf: (libc)Operations on Complex.
* conj: (libc)Operations on Complex.
* conjl: (libc)Operations on Complex.
* connect: (libc)Connecting.
* copysignf: (libc)FP Bit Twiddling.
* copysign: (libc)FP Bit Twiddling.
* copysignl: (libc)FP Bit Twiddling.
* cosf: (libc)Trig Functions.
* coshf: (libc)Hyperbolic Functions.
* cosh: (libc)Hyperbolic Functions.
* coshl: (libc)Hyperbolic Functions.
* cos: (libc)Trig Functions.
* cosl: (libc)Trig Functions.
* cpowf: (libc)Exponents and Logarithms.
* cpow: (libc)Exponents and Logarithms.
* cpowl: (libc)Exponents and Logarithms.
* cprojf: (libc)Operations on Complex.
* cproj: (libc)Operations on Complex.
* cprojl: (libc)Operations on Complex.
* CPU_CLR: (libc)CPU Affinity.
* CPU_ISSET: (libc)CPU Affinity.
* CPU_SET: (libc)CPU Affinity.
* CPU_SETSIZE: (libc)CPU Affinity.
* CPU_ZERO: (libc)CPU Affinity.
* CREAD: (libc)Control Modes.
* crealf: (libc)Operations on Complex.
* creal: (libc)Operations on Complex.
* creall: (libc)Operations on Complex.
* creat64: (libc)Opening and Closing Files.
* creat: (libc)Opening and Closing Files.
* CRTS_IFLOW: (libc)Control Modes.
* crypt: (libc)crypt.
* crypt_r: (libc)crypt.
* CS5: (libc)Control Modes.
* CS6: (libc)Control Modes.
* CS7: (libc)Control Modes.
* CS8: (libc)Control Modes.
* csinf: (libc)Trig Functions.
* csinhf: (libc)Hyperbolic Functions.
* csinh: (libc)Hyperbolic Functions.
* csinhl: (libc)Hyperbolic Functions.
* csin: (libc)Trig Functions.
* csinl: (libc)Trig Functions.
* CSIZE: (libc)Control Modes.
* csqrtf: (libc)Exponents and Logarithms.
* csqrt: (libc)Exponents and Logarithms.
* csqrtl: (libc)Exponents and Logarithms.
* CSTOPB: (libc)Control Modes.
* ctanf: (libc)Trig Functions.
* ctanhf: (libc)Hyperbolic Functions.
* ctanh: (libc)Hyperbolic Functions.
* ctanhl: (libc)Hyperbolic Functions.
* ctan: (libc)Trig Functions.
* ctanl: (libc)Trig Functions.
* ctermid: (libc)Identifying the Terminal.
* ctime: (libc)Formatting Calendar Time.
* ctime_r: (libc)Formatting Calendar Time.
* cuserid: (libc)Who Logged In.
* dcgettext: (libc)Translation with gettext.
* dcngettext: (libc)Advanced gettext functions.
* DES_FAILED: (libc)DES Encryption.
* des_setparity: (libc)DES Encryption.
* dgettext: (libc)Translation with gettext.
* difftime: (libc)Elapsed Time.
* dirfd: (libc)Opening a Directory.
* dirname: (libc)Finding Tokens in a String.
* div: (libc)Integer Division.
* dngettext: (libc)Advanced gettext functions.
* drand48: (libc)SVID Random.
* drand48_r: (libc)SVID Random.
* dremf: (libc)Remainder Functions.
* drem: (libc)Remainder Functions.
* dreml: (libc)Remainder Functions.
* DTTOIF: (libc)Directory Entries.
* dup2: (libc)Duplicating Descriptors.
* dup: (libc)Duplicating Descriptors.
* E2BIG: (libc)Error Codes.
* EACCES: (libc)Error Codes.
* EADDRINUSE: (libc)Error Codes.
* EADDRNOTAVAIL: (libc)Error Codes.
* EADV: (libc)Error Codes.
* EAFNOSUPPORT: (libc)Error Codes.
* EAGAIN: (libc)Error Codes.
* EALREADY: (libc)Error Codes.
* EAUTH: (libc)Error Codes.
* EBACKGROUND: (libc)Error Codes.
* EBADE: (libc)Error Codes.
* EBADFD: (libc)Error Codes.
* EBADF: (libc)Error Codes.
* EBADMSG: (libc)Error Codes.
* EBADR: (libc)Error Codes.
* EBADRPC: (libc)Error Codes.
* EBADRQC: (libc)Error Codes.
* EBADSLT: (libc)Error Codes.
* EBFONT: (libc)Error Codes.
* EBUSY: (libc)Error Codes.
* ECANCELED: (libc)Error Codes.
* ecb_crypt: (libc)DES Encryption.
* ECHILD: (libc)Error Codes.
* ECHOCTL: (libc)Local Modes.
* ECHOE: (libc)Local Modes.
* ECHOKE: (libc)Local Modes.
* ECHOK: (libc)Local Modes.
* ECHO: (libc)Local Modes.
* ECHONL: (libc)Local Modes.
* ECHOPRT: (libc)Local Modes.
* ECHRNG: (libc)Error Codes.
* ECOMM: (libc)Error Codes.
* ECONNABORTED: (libc)Error Codes.
* ECONNREFUSED: (libc)Error Codes.
* ECONNRESET: (libc)Error Codes.
* ecvt: (libc)System V Number Conversion.
* ecvt_r: (libc)System V Number Conversion.
* EDEADLK: (libc)Error Codes.
* EDEADLOCK: (libc)Error Codes.
* EDESTADDRREQ: (libc)Error Codes.
* EDIED: (libc)Error Codes.
* ED: (libc)Error Codes.
* EDOM: (libc)Error Codes.
* EDOTDOT: (libc)Error Codes.
* EDQUOT: (libc)Error Codes.
* EEXIST: (libc)Error Codes.
* EFAULT: (libc)Error Codes.
* EFBIG: (libc)Error Codes.
* EFTYPE: (libc)Error Codes.
* EGRATUITOUS: (libc)Error Codes.
* EGREGIOUS: (libc)Error Codes.
* EHOSTDOWN: (libc)Error Codes.
* EHOSTUNREACH: (libc)Error Codes.
* EHWPOISON: (libc)Error Codes.
* EIDRM: (libc)Error Codes.
* EIEIO: (libc)Error Codes.
* EILSEQ: (libc)Error Codes.
* EINPROGRESS: (libc)Error Codes.
* EINTR: (libc)Error Codes.
* EINVAL: (libc)Error Codes.
* EIO: (libc)Error Codes.
* EISCONN: (libc)Error Codes.
* EISDIR: (libc)Error Codes.
* EISNAM: (libc)Error Codes.
* EKEYEXPIRED: (libc)Error Codes.
* EKEYREJECTED: (libc)Error Codes.
* EKEYREVOKED: (libc)Error Codes.
* EL2HLT: (libc)Error Codes.
* EL2NSYNC: (libc)Error Codes.
* EL3HLT: (libc)Error Codes.
* EL3RST: (libc)Error Codes.
* ELIBACC: (libc)Error Codes.
* ELIBBAD: (libc)Error Codes.
* ELIBEXEC: (libc)Error Codes.
* ELIBMAX: (libc)Error Codes.
* ELIBSCN: (libc)Error Codes.
* ELNRNG: (libc)Error Codes.
* ELOOP: (libc)Error Codes.
* EMEDIUMTYPE: (libc)Error Codes.
* EMFILE: (libc)Error Codes.
* EMLINK: (libc)Error Codes.
* EMSGSIZE: (libc)Error Codes.
* EMULTIHOP: (libc)Error Codes.
* ENAMETOOLONG: (libc)Error Codes.
* ENAVAIL: (libc)Error Codes.
* encrypt: (libc)DES Encryption.
* encrypt_r: (libc)DES Encryption.
* endfsent: (libc)fstab.
* endgrent: (libc)Scanning All Groups.
* endhostent: (libc)Host Names.
* endmntent: (libc)mtab.
* endnetent: (libc)Networks Database.
* endnetgrent: (libc)Lookup Netgroup.
* endprotoent: (libc)Protocols Database.
* endpwent: (libc)Scanning All Users.
* endservent: (libc)Services Database.
* endutent: (libc)Manipulating the Database.
* endutxent: (libc)XPG Functions.
* ENEEDAUTH: (libc)Error Codes.
* ENETDOWN: (libc)Error Codes.
* ENETRESET: (libc)Error Codes.
* ENETUNREACH: (libc)Error Codes.
* ENFILE: (libc)Error Codes.
* ENOANO: (libc)Error Codes.
* ENOBUFS: (libc)Error Codes.
* ENOCSI: (libc)Error Codes.
* ENODATA: (libc)Error Codes.
* ENODEV: (libc)Error Codes.
* ENOENT: (libc)Error Codes.
* ENOEXEC: (libc)Error Codes.
* ENOKEY: (libc)Error Codes.
* ENOLCK: (libc)Error Codes.
* ENOLINK: (libc)Error Codes.
* ENOMEDIUM: (libc)Error Codes.
* ENOMEM: (libc)Error Codes.
* ENOMSG: (libc)Error Codes.
* ENONET: (libc)Error Codes.
* ENOPKG: (libc)Error Codes.
* ENOPROTOOPT: (libc)Error Codes.
* ENOSPC: (libc)Error Codes.
* ENOSR: (libc)Error Codes.
* ENOSTR: (libc)Error Codes.
* ENOSYS: (libc)Error Codes.
* ENOTBLK: (libc)Error Codes.
* ENOTCONN: (libc)Error Codes.
* ENOTDIR: (libc)Error Codes.
* ENOTEMPTY: (libc)Error Codes.
* ENOTNAM: (libc)Error Codes.
* ENOTRECOVERABLE: (libc)Error Codes.
* ENOTSOCK: (libc)Error Codes.
* ENOTSUP: (libc)Error Codes.
* ENOTTY: (libc)Error Codes.
* ENOTUNIQ: (libc)Error Codes.
* envz_add: (libc)Envz Functions.
* envz_entry: (libc)Envz Functions.
* envz_get: (libc)Envz Functions.
* envz_merge: (libc)Envz Functions.
* envz_remove: (libc)Envz Functions.
* envz_strip: (libc)Envz Functions.
* ENXIO: (libc)Error Codes.
* EOF: (libc)EOF and Errors.
* EOPNOTSUPP: (libc)Error Codes.
* EOVERFLOW: (libc)Error Codes.
* EOWNERDEAD: (libc)Error Codes.
* EPERM: (libc)Error Codes.
* EPFNOSUPPORT: (libc)Error Codes.
* EPIPE: (libc)Error Codes.
* EPROCLIM: (libc)Error Codes.
* EPROCUNAVAIL: (libc)Error Codes.
* EPROGMISMATCH: (libc)Error Codes.
* EPROGUNAVAIL: (libc)Error Codes.
* EPROTO: (libc)Error Codes.
* EPROTONOSUPPORT: (libc)Error Codes.
* EPROTOTYPE: (libc)Error Codes.
* EQUIV_CLASS_MAX: (libc)Utility Limits.
* erand48: (libc)SVID Random.
* erand48_r: (libc)SVID Random.
* ERANGE: (libc)Error Codes.
* EREMCHG: (libc)Error Codes.
* EREMOTEIO: (libc)Error Codes.
* EREMOTE: (libc)Error Codes.
* ERESTART: (libc)Error Codes.
* erfcf: (libc)Special Functions.
* erfc: (libc)Special Functions.
* erfcl: (libc)Special Functions.
* erff: (libc)Special Functions.
* ERFKILL: (libc)Error Codes.
* erf: (libc)Special Functions.
* erfl: (libc)Special Functions.
* EROFS: (libc)Error Codes.
* ERPCMISMATCH: (libc)Error Codes.
* err: (libc)Error Messages.
* errno: (libc)Checking for Errors.
* error_at_line: (libc)Error Messages.
* error: (libc)Error Messages.
* errx: (libc)Error Messages.
* ESHUTDOWN: (libc)Error Codes.
* ESOCKTNOSUPPORT: (libc)Error Codes.
* ESPIPE: (libc)Error Codes.
* ESRCH: (libc)Error Codes.
* ESRMNT: (libc)Error Codes.
* ESTALE: (libc)Error Codes.
* ESTRPIPE: (libc)Error Codes.
* ETIMEDOUT: (libc)Error Codes.
* ETIME: (libc)Error Codes.
* ETOOMANYREFS: (libc)Error Codes.
* ETXTBSY: (libc)Error Codes.
* EUCLEAN: (libc)Error Codes.
* EUNATCH: (libc)Error Codes.
* EUSERS: (libc)Error Codes.
* EWOULDBLOCK: (libc)Error Codes.
* EXDEV: (libc)Error Codes.
* execle: (libc)Executing a File.
* execl: (libc)Executing a File.
* execlp: (libc)Executing a File.
* execve: (libc)Executing a File.
* execv: (libc)Executing a File.
* execvp: (libc)Executing a File.
* EXFULL: (libc)Error Codes.
* EXIT_FAILURE: (libc)Exit Status.
* exit: (libc)Normal Termination.
* _exit: (libc)Termination Internals.
* _Exit: (libc)Termination Internals.
* EXIT_SUCCESS: (libc)Exit Status.
* exp10f: (libc)Exponents and Logarithms.
* exp10: (libc)Exponents and Logarithms.
* exp10l: (libc)Exponents and Logarithms.
* exp2f: (libc)Exponents and Logarithms.
* exp2: (libc)Exponents and Logarithms.
* exp2l: (libc)Exponents and Logarithms.
* expf: (libc)Exponents and Logarithms.
* exp: (libc)Exponents and Logarithms.
* explicit_bzero: (libc)Erasing Sensitive Data.
* expl: (libc)Exponents and Logarithms.
* expm1f: (libc)Exponents and Logarithms.
* expm1: (libc)Exponents and Logarithms.
* expm1l: (libc)Exponents and Logarithms.
* EXPR_NEST_MAX: (libc)Utility Limits.
* fabsf: (libc)Absolute Value.
* fabs: (libc)Absolute Value.
* fabsl: (libc)Absolute Value.
* __fbufsize: (libc)Controlling Buffering.
* fchdir: (libc)Working Directory.
* fchmod: (libc)Setting Permissions.
* fchown: (libc)File Owner.
* fcloseall: (libc)Closing Streams.
* fclose: (libc)Closing Streams.
* fcntl: (libc)Control Operations.
* fcvt: (libc)System V Number Conversion.
* fcvt_r: (libc)System V Number Conversion.
* fdatasync: (libc)Synchronizing I/O.
* FD_CLOEXEC: (libc)Descriptor Flags.
* FD_CLR: (libc)Waiting for I/O.
* fdimf: (libc)Misc FP Arithmetic.
* fdim: (libc)Misc FP Arithmetic.
* fdiml: (libc)Misc FP Arithmetic.
* FD_ISSET: (libc)Waiting for I/O.
* fdopendir: (libc)Opening a Directory.
* fdopen: (libc)Descriptors and Streams.
* FD_SET: (libc)Waiting for I/O.
* FD_SETSIZE: (libc)Waiting for I/O.
* F_DUPFD: (libc)Duplicating Descriptors.
* FD_ZERO: (libc)Waiting for I/O.
* feclearexcept: (libc)Status bit operations.
* fedisableexcept: (libc)Control Functions.
* feenableexcept: (libc)Control Functions.
* fegetenv: (libc)Control Functions.
* fegetexceptflag: (libc)Status bit operations.
* fegetexcept: (libc)Control Functions.
* fegetmode: (libc)Control Functions.
* fegetround: (libc)Rounding.
* feholdexcept: (libc)Control Functions.
* feof: (libc)EOF and Errors.
* feof_unlocked: (libc)EOF and Errors.
* feraiseexcept: (libc)Status bit operations.
* ferror: (libc)EOF and Errors.
* ferror_unlocked: (libc)EOF and Errors.
* fesetenv: (libc)Control Functions.
* fesetexceptflag: (libc)Status bit operations.
* fesetexcept: (libc)Status bit operations.
* fesetmode: (libc)Control Functions.
* fesetround: (libc)Rounding.
* FE_SNANS_ALWAYS_SIGNAL: (libc)Infinity and NaN.
* fetestexceptflag: (libc)Status bit operations.
* fetestexcept: (libc)Status bit operations.
* feupdateenv: (libc)Control Functions.
* fflush: (libc)Flushing Buffers.
* fflush_unlocked: (libc)Flushing Buffers.
* fgetc: (libc)Character Input.
* fgetc_unlocked: (libc)Character Input.
* F_GETFD: (libc)Descriptor Flags.
* F_GETFL: (libc)Getting File Status Flags.
* fgetgrent: (libc)Scanning All Groups.
* fgetgrent_r: (libc)Scanning All Groups.
* F_GETLK: (libc)File Locks.
* F_GETOWN: (libc)Interrupt Input.
* fgetpos64: (libc)Portable Positioning.
* fgetpos: (libc)Portable Positioning.
* fgetpwent: (libc)Scanning All Users.
* fgetpwent_r: (libc)Scanning All Users.
* fgets: (libc)Line Input.
* fgets_unlocked: (libc)Line Input.
* fgetwc: (libc)Character Input.
* fgetwc_unlocked: (libc)Character Input.
* fgetws: (libc)Line Input.
* fgetws_unlocked: (libc)Line Input.
* FILENAME_MAX: (libc)Limits for Files.
* fileno: (libc)Descriptors and Streams.
* fileno_unlocked: (libc)Descriptors and Streams.
* finitef: (libc)Floating Point Classes.
* finite: (libc)Floating Point Classes.
* finitel: (libc)Floating Point Classes.
* __flbf: (libc)Controlling Buffering.
* flockfile: (libc)Streams and Threads.
* floorf: (libc)Rounding Functions.
* floor: (libc)Rounding Functions.
* floorl: (libc)Rounding Functions.
* _flushlbf: (libc)Flushing Buffers.
* FLUSHO: (libc)Local Modes.
* fmaf: (libc)Misc FP Arithmetic.
* fma: (libc)Misc FP Arithmetic.
* fmal: (libc)Misc FP Arithmetic.
* fmaxf: (libc)Misc FP Arithmetic.
* fmax: (libc)Misc FP Arithmetic.
* fmaxl: (libc)Misc FP Arithmetic.
* fmaxmagf: (libc)Misc FP Arithmetic.
* fmaxmag: (libc)Misc FP Arithmetic.
* fmaxmagl: (libc)Misc FP Arithmetic.
* fmemopen: (libc)String Streams.
* fminf: (libc)Misc FP Arithmetic.
* fmin: (libc)Misc FP Arithmetic.
* fminl: (libc)Misc FP Arithmetic.
* fminmagf: (libc)Misc FP Arithmetic.
* fminmag: (libc)Misc FP Arithmetic.
* fminmagl: (libc)Misc FP Arithmetic.
* fmodf: (libc)Remainder Functions.
* fmod: (libc)Remainder Functions.
* fmodl: (libc)Remainder Functions.
* fmtmsg: (libc)Printing Formatted Messages.
* fnmatch: (libc)Wildcard Matching.
* F_OFD_GETLK: (libc)Open File Description Locks.
* F_OFD_SETLK: (libc)Open File Description Locks.
* F_OFD_SETLKW: (libc)Open File Description Locks.
* F_OK: (libc)Testing File Access.
* fopen64: (libc)Opening Streams.
* fopencookie: (libc)Streams and Cookies.
* fopen: (libc)Opening Streams.
* FOPEN_MAX: (libc)Opening Streams.
* fork: (libc)Creating a Process.
* forkpty: (libc)Pseudo-Terminal Pairs.
* fpathconf: (libc)Pathconf.
* fpclassify: (libc)Floating Point Classes.
* __fpending: (libc)Controlling Buffering.
* FP_ILOGB0: (libc)Exponents and Logarithms.
* FP_ILOGBNAN: (libc)Exponents and Logarithms.
* FP_LLOGB0: (libc)Exponents and Logarithms.
* FP_LLOGBNAN: (libc)Exponents and Logarithms.
* fprintf: (libc)Formatted Output Functions.
* __fpurge: (libc)Flushing Buffers.
* fputc: (libc)Simple Output.
* fputc_unlocked: (libc)Simple Output.
* fputs: (libc)Simple Output.
* fputs_unlocked: (libc)Simple Output.
* fputwc: (libc)Simple Output.
* fputwc_unlocked: (libc)Simple Output.
* fputws: (libc)Simple Output.
* fputws_unlocked: (libc)Simple Output.
* __freadable: (libc)Opening Streams.
* __freading: (libc)Opening Streams.
* fread: (libc)Block Input/Output.
* fread_unlocked: (libc)Block Input/Output.
* free: (libc)Freeing after Malloc.
* freopen64: (libc)Opening Streams.
* freopen: (libc)Opening Streams.
* frexpf: (libc)Normalization Functions.
* frexp: (libc)Normalization Functions.
* frexpl: (libc)Normalization Functions.
* fromfpf: (libc)Rounding Functions.
* fromfp: (libc)Rounding Functions.
* fromfpl: (libc)Rounding Functions.
* fromfpxf: (libc)Rounding Functions.
* fromfpx: (libc)Rounding Functions.
* fromfpxl: (libc)Rounding Functions.
* fscanf: (libc)Formatted Input Functions.
* fseek: (libc)File Positioning.
* fseeko64: (libc)File Positioning.
* fseeko: (libc)File Positioning.
* F_SETFD: (libc)Descriptor Flags.
* F_SETFL: (libc)Getting File Status Flags.
* F_SETLK: (libc)File Locks.
* F_SETLKW: (libc)File Locks.
* __fsetlocking: (libc)Streams and Threads.
* F_SETOWN: (libc)Interrupt Input.
* fsetpos64: (libc)Portable Positioning.
* fsetpos: (libc)Portable Positioning.
* fstat64: (libc)Reading Attributes.
* fstat: (libc)Reading Attributes.
* fsync: (libc)Synchronizing I/O.
* ftell: (libc)File Positioning.
* ftello64: (libc)File Positioning.
* ftello: (libc)File Positioning.
* ftruncate64: (libc)File Size.
* ftruncate: (libc)File Size.
* ftrylockfile: (libc)Streams and Threads.
* ftw64: (libc)Working with Directory Trees.
* ftw: (libc)Working with Directory Trees.
* funlockfile: (libc)Streams and Threads.
* futimes: (libc)File Times.
* fwide: (libc)Streams and I18N.
* fwprintf: (libc)Formatted Output Functions.
* __fwritable: (libc)Opening Streams.
* fwrite: (libc)Block Input/Output.
* fwrite_unlocked: (libc)Block Input/Output.
* __fwriting: (libc)Opening Streams.
* fwscanf: (libc)Formatted Input Functions.
* gammaf: (libc)Special Functions.
* gamma: (libc)Special Functions.
* gammal: (libc)Special Functions.
* __gconv_end_fct: (libc)glibc iconv Implementation.
* __gconv_fct: (libc)glibc iconv Implementation.
* __gconv_init_fct: (libc)glibc iconv Implementation.
* gcvt: (libc)System V Number Conversion.
* getauxval: (libc)Auxiliary Vector.
* get_avphys_pages: (libc)Query Memory Parameters.
* getchar: (libc)Character Input.
* getchar_unlocked: (libc)Character Input.
* getc: (libc)Character Input.
* getcontext: (libc)System V contexts.
* getc_unlocked: (libc)Character Input.
* get_current_dir_name: (libc)Working Directory.
* getcwd: (libc)Working Directory.
* getdate: (libc)General Time String Parsing.
* getdate_r: (libc)General Time String Parsing.
* getdelim: (libc)Line Input.
* getdomainnname: (libc)Host Identification.
* getegid: (libc)Reading Persona.
* getentropy: (libc)Unpredictable Bytes.
* getenv: (libc)Environment Access.
* geteuid: (libc)Reading Persona.
* getfsent: (libc)fstab.
* getfsfile: (libc)fstab.
* getfsspec: (libc)fstab.
* getgid: (libc)Reading Persona.
* getgrent: (libc)Scanning All Groups.
* getgrent_r: (libc)Scanning All Groups.
* getgrgid: (libc)Lookup Group.
* getgrgid_r: (libc)Lookup Group.
* getgrnam: (libc)Lookup Group.
* getgrnam_r: (libc)Lookup Group.
* getgrouplist: (libc)Setting Groups.
* getgroups: (libc)Reading Persona.
* gethostbyaddr: (libc)Host Names.
* gethostbyaddr_r: (libc)Host Names.
* gethostbyname2: (libc)Host Names.
* gethostbyname2_r: (libc)Host Names.
* gethostbyname: (libc)Host Names.
* gethostbyname_r: (libc)Host Names.
* gethostent: (libc)Host Names.
* gethostid: (libc)Host Identification.
* gethostname: (libc)Host Identification.
* getitimer: (libc)Setting an Alarm.
* getline: (libc)Line Input.
* getloadavg: (libc)Processor Resources.
* getlogin: (libc)Who Logged In.
* getmntent: (libc)mtab.
* getmntent_r: (libc)mtab.
* getnetbyaddr: (libc)Networks Database.
* getnetbyname: (libc)Networks Database.
* getnetent: (libc)Networks Database.
* getnetgrent: (libc)Lookup Netgroup.
* getnetgrent_r: (libc)Lookup Netgroup.
* get_nprocs_conf: (libc)Processor Resources.
* get_nprocs: (libc)Processor Resources.
* getopt: (libc)Using Getopt.
* getopt_long: (libc)Getopt Long Options.
* getopt_long_only: (libc)Getopt Long Options.
* getpagesize: (libc)Query Memory Parameters.
* getpass: (libc)getpass.
* getpayloadf: (libc)FP Bit Twiddling.
* getpayload: (libc)FP Bit Twiddling.
* getpayloadl: (libc)FP Bit Twiddling.
* getpeername: (libc)Who is Connected.
* getpgid: (libc)Process Group Functions.
* getpgrp: (libc)Process Group Functions.
* get_phys_pages: (libc)Query Memory Parameters.
* getpid: (libc)Process Identification.
* getppid: (libc)Process Identification.
* getpriority: (libc)Traditional Scheduling Functions.
* getprotobyname: (libc)Protocols Database.
* getprotobynumber: (libc)Protocols Database.
* getprotoent: (libc)Protocols Database.
* getpt: (libc)Allocation.
* getpwent: (libc)Scanning All Users.
* getpwent_r: (libc)Scanning All Users.
* getpwnam: (libc)Lookup User.
* getpwnam_r: (libc)Lookup User.
* getpwuid: (libc)Lookup User.
* getpwuid_r: (libc)Lookup User.
* getrandom: (libc)Unpredictable Bytes.
* getrlimit64: (libc)Limits on Resources.
* getrlimit: (libc)Limits on Resources.
* getrusage: (libc)Resource Usage.
* getservbyname: (libc)Services Database.
* getservbyport: (libc)Services Database.
* getservent: (libc)Services Database.
* getsid: (libc)Process Group Functions.
* gets: (libc)Line Input.
* getsockname: (libc)Reading Address.
* getsockopt: (libc)Socket Option Functions.
* getsubopt: (libc)Suboptions.
* gettext: (libc)Translation with gettext.
* gettimeofday: (libc)High-Resolution Calendar.
* getuid: (libc)Reading Persona.
* getumask: (libc)Setting Permissions.
* getutent: (libc)Manipulating the Database.
* getutent_r: (libc)Manipulating the Database.
* getutid: (libc)Manipulating the Database.
* getutid_r: (libc)Manipulating the Database.
* getutline: (libc)Manipulating the Database.
* getutline_r: (libc)Manipulating the Database.
* getutmp: (libc)XPG Functions.
* getutmpx: (libc)XPG Functions.
* getutxent: (libc)XPG Functions.
* getutxid: (libc)XPG Functions.
* getutxline: (libc)XPG Functions.
* getwchar: (libc)Character Input.
* getwchar_unlocked: (libc)Character Input.
* getwc: (libc)Character Input.
* getwc_unlocked: (libc)Character Input.
* getwd: (libc)Working Directory.
* getw: (libc)Character Input.
* glob64: (libc)Calling Glob.
* globfree64: (libc)More Flags for Globbing.
* globfree: (libc)More Flags for Globbing.
* glob: (libc)Calling Glob.
* gmtime: (libc)Broken-down Time.
* gmtime_r: (libc)Broken-down Time.
* grantpt: (libc)Allocation.
* gsignal: (libc)Signaling Yourself.
* gtty: (libc)BSD Terminal Modes.
* hasmntopt: (libc)mtab.
* hcreate: (libc)Hash Search Function.
* hcreate_r: (libc)Hash Search Function.
* hdestroy: (libc)Hash Search Function.
* hdestroy_r: (libc)Hash Search Function.
* hsearch: (libc)Hash Search Function.
* hsearch_r: (libc)Hash Search Function.
* htonl: (libc)Byte Order.
* htons: (libc)Byte Order.
* HUGE_VALF: (libc)Math Error Reporting.
* HUGE_VAL: (libc)Math Error Reporting.
* HUGE_VALL: (libc)Math Error Reporting.
* HUPCL: (libc)Control Modes.
* hypotf: (libc)Exponents and Logarithms.
* hypot: (libc)Exponents and Logarithms.
* hypotl: (libc)Exponents and Logarithms.
* ICANON: (libc)Local Modes.
* iconv_close: (libc)Generic Conversion Interface.
* iconv: (libc)Generic Conversion Interface.
* iconv_open: (libc)Generic Conversion Interface.
* ICRNL: (libc)Input Modes.
* IEXTEN: (libc)Local Modes.
* if_freenameindex: (libc)Interface Naming.
* if_indextoname: (libc)Interface Naming.
* if_nameindex: (libc)Interface Naming.
* if_nametoindex: (libc)Interface Naming.
* IFNAMSIZ: (libc)Interface Naming.
* IFTODT: (libc)Directory Entries.
* IGNBRK: (libc)Input Modes.
* IGNCR: (libc)Input Modes.
* IGNPAR: (libc)Input Modes.
* I: (libc)Complex Numbers.
* ilogbf: (libc)Exponents and Logarithms.
* ilogb: (libc)Exponents and Logarithms.
* ilogbl: (libc)Exponents and Logarithms.
* _Imaginary_I: (libc)Complex Numbers.
* imaxabs: (libc)Absolute Value.
* IMAXBEL: (libc)Input Modes.
* imaxdiv: (libc)Integer Division.
* in6addr_any: (libc)Host Address Data Type.
* in6addr_loopback: (libc)Host Address Data Type.
* INADDR_ANY: (libc)Host Address Data Type.
* INADDR_BROADCAST: (libc)Host Address Data Type.
* INADDR_LOOPBACK: (libc)Host Address Data Type.
* INADDR_NONE: (libc)Host Address Data Type.
* index: (libc)Search Functions.
* inet_addr: (libc)Host Address Functions.
* inet_aton: (libc)Host Address Functions.
* inet_lnaof: (libc)Host Address Functions.
* inet_makeaddr: (libc)Host Address Functions.
* inet_netof: (libc)Host Address Functions.
* inet_network: (libc)Host Address Functions.
* inet_ntoa: (libc)Host Address Functions.
* inet_ntop: (libc)Host Address Functions.
* inet_pton: (libc)Host Address Functions.
* INFINITY: (libc)Infinity and NaN.
* initgroups: (libc)Setting Groups.
* initstate: (libc)BSD Random.
* initstate_r: (libc)BSD Random.
* INLCR: (libc)Input Modes.
* innetgr: (libc)Netgroup Membership.
* INPCK: (libc)Input Modes.
* ioctl: (libc)IOCTLs.
* _IOFBF: (libc)Controlling Buffering.
* _IOLBF: (libc)Controlling Buffering.
* _IONBF: (libc)Controlling Buffering.
* IPPORT_RESERVED: (libc)Ports.
* IPPORT_USERRESERVED: (libc)Ports.
* isalnum: (libc)Classification of Characters.
* isalpha: (libc)Classification of Characters.
* isascii: (libc)Classification of Characters.
* isatty: (libc)Is It a Terminal.
* isblank: (libc)Classification of Characters.
* iscanonical: (libc)Floating Point Classes.
* iscntrl: (libc)Classification of Characters.
* isdigit: (libc)Classification of Characters.
* iseqsig: (libc)FP Comparison Functions.
* isfinite: (libc)Floating Point Classes.
* isgraph: (libc)Classification of Characters.
* isgreaterequal: (libc)FP Comparison Functions.
* isgreater: (libc)FP Comparison Functions.
* ISIG: (libc)Local Modes.
* isinff: (libc)Floating Point Classes.
* isinf: (libc)Floating Point Classes.
* isinfl: (libc)Floating Point Classes.
* islessequal: (libc)FP Comparison Functions.
* islessgreater: (libc)FP Comparison Functions.
* isless: (libc)FP Comparison Functions.
* islower: (libc)Classification of Characters.
* isnanf: (libc)Floating Point Classes.
* isnan: (libc)Floating Point Classes.
* isnan: (libc)Floating Point Classes.
* isnanl: (libc)Floating Point Classes.
* isnormal: (libc)Floating Point Classes.
* isprint: (libc)Classification of Characters.
* ispunct: (libc)Classification of Characters.
* issignaling: (libc)Floating Point Classes.
* isspace: (libc)Classification of Characters.
* issubnormal: (libc)Floating Point Classes.
* ISTRIP: (libc)Input Modes.
* isunordered: (libc)FP Comparison Functions.
* isupper: (libc)Classification of Characters.
* iswalnum: (libc)Classification of Wide Characters.
* iswalpha: (libc)Classification of Wide Characters.
* iswblank: (libc)Classification of Wide Characters.
* iswcntrl: (libc)Classification of Wide Characters.
* iswctype: (libc)Classification of Wide Characters.
* iswdigit: (libc)Classification of Wide Characters.
* iswgraph: (libc)Classification of Wide Characters.
* iswlower: (libc)Classification of Wide Characters.
* iswprint: (libc)Classification of Wide Characters.
* iswpunct: (libc)Classification of Wide Characters.
* iswspace: (libc)Classification of Wide Characters.
* iswupper: (libc)Classification of Wide Characters.
* iswxdigit: (libc)Classification of Wide Characters.
* isxdigit: (libc)Classification of Characters.
* iszero: (libc)Floating Point Classes.
* IXANY: (libc)Input Modes.
* IXOFF: (libc)Input Modes.
* IXON: (libc)Input Modes.
* j0f: (libc)Special Functions.
* j0: (libc)Special Functions.
* j0l: (libc)Special Functions.
* j1f: (libc)Special Functions.
* j1: (libc)Special Functions.
* j1l: (libc)Special Functions.
* jnf: (libc)Special Functions.
* jn: (libc)Special Functions.
* jnl: (libc)Special Functions.
* jrand48: (libc)SVID Random.
* jrand48_r: (libc)SVID Random.
* kill: (libc)Signaling Another Process.
* killpg: (libc)Signaling Another Process.
* l64a: (libc)Encode Binary Data.
* labs: (libc)Absolute Value.
* lcong48: (libc)SVID Random.
* lcong48_r: (libc)SVID Random.
* L_ctermid: (libc)Identifying the Terminal.
* L_cuserid: (libc)Who Logged In.
* ldexpf: (libc)Normalization Functions.
* ldexp: (libc)Normalization Functions.
* ldexpl: (libc)Normalization Functions.
* ldiv: (libc)Integer Division.
* lfind: (libc)Array Search Function.
* lgammaf: (libc)Special Functions.
* lgammaf_r: (libc)Special Functions.
* lgamma: (libc)Special Functions.
* lgammal: (libc)Special Functions.
* lgammal_r: (libc)Special Functions.
* lgamma_r: (libc)Special Functions.
* LINE_MAX: (libc)Utility Limits.
* link: (libc)Hard Links.
* LINK_MAX: (libc)Limits for Files.
* lio_listio64: (libc)Asynchronous Reads/Writes.
* lio_listio: (libc)Asynchronous Reads/Writes.
* listen: (libc)Listening.
* llabs: (libc)Absolute Value.
* lldiv: (libc)Integer Division.
* llogbf: (libc)Exponents and Logarithms.
* llogb: (libc)Exponents and Logarithms.
* llogbl: (libc)Exponents and Logarithms.
* llrintf: (libc)Rounding Functions.
* llrint: (libc)Rounding Functions.
* llrintl: (libc)Rounding Functions.
* llroundf: (libc)Rounding Functions.
* llround: (libc)Rounding Functions.
* llroundl: (libc)Rounding Functions.
* localeconv: (libc)The Lame Way to Locale Data.
* localtime: (libc)Broken-down Time.
* localtime_r: (libc)Broken-down Time.
* log10f: (libc)Exponents and Logarithms.
* log10: (libc)Exponents and Logarithms.
* log10l: (libc)Exponents and Logarithms.
* log1pf: (libc)Exponents and Logarithms.
* log1p: (libc)Exponents and Logarithms.
* log1pl: (libc)Exponents and Logarithms.
* log2f: (libc)Exponents and Logarithms.
* log2: (libc)Exponents and Logarithms.
* log2l: (libc)Exponents and Logarithms.
* logbf: (libc)Exponents and Logarithms.
* logb: (libc)Exponents and Logarithms.
* logbl: (libc)Exponents and Logarithms.
* logf: (libc)Exponents and Logarithms.
* login: (libc)Logging In and Out.
* login_tty: (libc)Logging In and Out.
* log: (libc)Exponents and Logarithms.
* logl: (libc)Exponents and Logarithms.
* logout: (libc)Logging In and Out.
* logwtmp: (libc)Logging In and Out.
* longjmp: (libc)Non-Local Details.
* lrand48: (libc)SVID Random.
* lrand48_r: (libc)SVID Random.
* lrintf: (libc)Rounding Functions.
* lrint: (libc)Rounding Functions.
* lrintl: (libc)Rounding Functions.
* lroundf: (libc)Rounding Functions.
* lround: (libc)Rounding Functions.
* lroundl: (libc)Rounding Functions.
* lsearch: (libc)Array Search Function.
* lseek64: (libc)File Position Primitive.
* lseek: (libc)File Position Primitive.
* lstat64: (libc)Reading Attributes.
* lstat: (libc)Reading Attributes.
* L_tmpnam: (libc)Temporary Files.
* lutimes: (libc)File Times.
* madvise: (libc)Memory-mapped I/O.
* makecontext: (libc)System V contexts.
* mallinfo: (libc)Statistics of Malloc.
* malloc: (libc)Basic Allocation.
* mallopt: (libc)Malloc Tunable Parameters.
* MAX_CANON: (libc)Limits for Files.
* MAX_INPUT: (libc)Limits for Files.
* MAXNAMLEN: (libc)Limits for Files.
* MAXSYMLINKS: (libc)Symbolic Links.
* MB_CUR_MAX: (libc)Selecting the Conversion.
* mblen: (libc)Non-reentrant Character Conversion.
* MB_LEN_MAX: (libc)Selecting the Conversion.
* mbrlen: (libc)Converting a Character.
* mbrtowc: (libc)Converting a Character.
* mbsinit: (libc)Keeping the state.
* mbsnrtowcs: (libc)Converting Strings.
* mbsrtowcs: (libc)Converting Strings.
* mbstowcs: (libc)Non-reentrant String Conversion.
* mbtowc: (libc)Non-reentrant Character Conversion.
* mcheck: (libc)Heap Consistency Checking.
* MDMBUF: (libc)Control Modes.
* memalign: (libc)Aligned Memory Blocks.
* memccpy: (libc)Copying Strings and Arrays.
* memchr: (libc)Search Functions.
* memcmp: (libc)String/Array Comparison.
* memcpy: (libc)Copying Strings and Arrays.
* memfrob: (libc)Trivial Encryption.
* memmem: (libc)Search Functions.
* memmove: (libc)Copying Strings and Arrays.
* mempcpy: (libc)Copying Strings and Arrays.
* memrchr: (libc)Search Functions.
* memset: (libc)Copying Strings and Arrays.
* mkdir: (libc)Creating Directories.
* mkdtemp: (libc)Temporary Files.
* mkfifo: (libc)FIFO Special Files.
* mknod: (libc)Making Special Files.
* mkstemp: (libc)Temporary Files.
* mktemp: (libc)Temporary Files.
* mktime: (libc)Broken-down Time.
* mlockall: (libc)Page Lock Functions.
* mlock: (libc)Page Lock Functions.
* mmap64: (libc)Memory-mapped I/O.
* mmap: (libc)Memory-mapped I/O.
* modff: (libc)Rounding Functions.
* modf: (libc)Rounding Functions.
* modfl: (libc)Rounding Functions.
* mount: (libc)Mount-Unmount-Remount.
* mprobe: (libc)Heap Consistency Checking.
* mrand48: (libc)SVID Random.
* mrand48_r: (libc)SVID Random.
* mremap: (libc)Memory-mapped I/O.
* MSG_DONTROUTE: (libc)Socket Data Options.
* MSG_OOB: (libc)Socket Data Options.
* MSG_PEEK: (libc)Socket Data Options.
* msync: (libc)Memory-mapped I/O.
* mtrace: (libc)Tracing malloc.
* munlockall: (libc)Page Lock Functions.
* munlock: (libc)Page Lock Functions.
* munmap: (libc)Memory-mapped I/O.
* muntrace: (libc)Tracing malloc.
* NAME_MAX: (libc)Limits for Files.
* nanf: (libc)FP Bit Twiddling.
* nan: (libc)FP Bit Twiddling.
* NAN: (libc)Infinity and NaN.
* nanl: (libc)FP Bit Twiddling.
* nanosleep: (libc)Sleeping.
* NCCS: (libc)Mode Data Types.
* nearbyintf: (libc)Rounding Functions.
* nearbyint: (libc)Rounding Functions.
* nearbyintl: (libc)Rounding Functions.
* nextafterf: (libc)FP Bit Twiddling.
* nextafter: (libc)FP Bit Twiddling.
* nextafterl: (libc)FP Bit Twiddling.
* nextdownf: (libc)FP Bit Twiddling.
* nextdown: (libc)FP Bit Twiddling.
* nextdownl: (libc)FP Bit Twiddling.
* nexttowardf: (libc)FP Bit Twiddling.
* nexttoward: (libc)FP Bit Twiddling.
* nexttowardl: (libc)FP Bit Twiddling.
* nextupf: (libc)FP Bit Twiddling.
* nextup: (libc)FP Bit Twiddling.
* nextupl: (libc)FP Bit Twiddling.
* nftw64: (libc)Working with Directory Trees.
* nftw: (libc)Working with Directory Trees.
* ngettext: (libc)Advanced gettext functions.
* NGROUPS_MAX: (libc)General Limits.
* nice: (libc)Traditional Scheduling Functions.
* nl_langinfo: (libc)The Elegant and Fast Way.
* NOFLSH: (libc)Local Modes.
* NOKERNINFO: (libc)Local Modes.
* nrand48: (libc)SVID Random.
* nrand48_r: (libc)SVID Random.
* NSIG: (libc)Standard Signals.
* ntohl: (libc)Byte Order.
* ntohs: (libc)Byte Order.
* ntp_adjtime: (libc)High Accuracy Clock.
* ntp_gettime: (libc)High Accuracy Clock.
* NULL: (libc)Null Pointer Constant.
* O_ACCMODE: (libc)Access Modes.
* O_APPEND: (libc)Operating Modes.
* O_ASYNC: (libc)Operating Modes.
* obstack_1grow_fast: (libc)Extra Fast Growing.
* obstack_1grow: (libc)Growing Objects.
* obstack_alignment_mask: (libc)Obstacks Data Alignment.
* obstack_alloc: (libc)Allocation in an Obstack.
* obstack_base: (libc)Status of an Obstack.
* obstack_blank_fast: (libc)Extra Fast Growing.
* obstack_blank: (libc)Growing Objects.
* obstack_chunk_size: (libc)Obstack Chunks.
* obstack_copy0: (libc)Allocation in an Obstack.
* obstack_copy: (libc)Allocation in an Obstack.
* obstack_finish: (libc)Growing Objects.
* obstack_free: (libc)Freeing Obstack Objects.
* obstack_grow0: (libc)Growing Objects.
* obstack_grow: (libc)Growing Objects.
* obstack_init: (libc)Preparing for Obstacks.
* obstack_int_grow_fast: (libc)Extra Fast Growing.
* obstack_int_grow: (libc)Growing Objects.
* obstack_next_free: (libc)Status of an Obstack.
* obstack_object_size: (libc)Growing Objects.
* obstack_object_size: (libc)Status of an Obstack.
* obstack_printf: (libc)Dynamic Output.
* obstack_ptr_grow_fast: (libc)Extra Fast Growing.
* obstack_ptr_grow: (libc)Growing Objects.
* obstack_room: (libc)Extra Fast Growing.
* obstack_vprintf: (libc)Variable Arguments Output.
* O_CREAT: (libc)Open-time Flags.
* O_EXCL: (libc)Open-time Flags.
* O_EXEC: (libc)Access Modes.
* O_EXLOCK: (libc)Open-time Flags.
* offsetof: (libc)Structure Measurement.
* O_FSYNC: (libc)Operating Modes.
* O_IGNORE_CTTY: (libc)Open-time Flags.
* O_NDELAY: (libc)Operating Modes.
* on_exit: (libc)Cleanups on Exit.
* ONLCR: (libc)Output Modes.
* O_NOATIME: (libc)Operating Modes.
* O_NOCTTY: (libc)Open-time Flags.
* ONOEOT: (libc)Output Modes.
* O_NOLINK: (libc)Open-time Flags.
* O_NONBLOCK: (libc)Open-time Flags.
* O_NONBLOCK: (libc)Operating Modes.
* O_NOTRANS: (libc)Open-time Flags.
* open64: (libc)Opening and Closing Files.
* opendir: (libc)Opening a Directory.
* open: (libc)Opening and Closing Files.
* openlog: (libc)openlog.
* OPEN_MAX: (libc)General Limits.
* open_memstream: (libc)String Streams.
* openpty: (libc)Pseudo-Terminal Pairs.
* OPOST: (libc)Output Modes.
* O_RDONLY: (libc)Access Modes.
* O_RDWR: (libc)Access Modes.
* O_READ: (libc)Access Modes.
* O_SHLOCK: (libc)Open-time Flags.
* O_SYNC: (libc)Operating Modes.
* O_TRUNC: (libc)Open-time Flags.
* O_WRITE: (libc)Access Modes.
* O_WRONLY: (libc)Access Modes.
* OXTABS: (libc)Output Modes.
* PA_FLAG_MASK: (libc)Parsing a Template String.
* PARENB: (libc)Control Modes.
* PARMRK: (libc)Input Modes.
* PARODD: (libc)Control Modes.
* parse_printf_format: (libc)Parsing a Template String.
* pathconf: (libc)Pathconf.
* PATH_MAX: (libc)Limits for Files.
* _PATH_UTMP: (libc)Manipulating the Database.
* _PATH_WTMP: (libc)Manipulating the Database.
* pause: (libc)Using Pause.
* pclose: (libc)Pipe to a Subprocess.
* PENDIN: (libc)Local Modes.
* perror: (libc)Error Messages.
* PF_FILE: (libc)Local Namespace Details.
* PF_INET6: (libc)Internet Namespace.
* PF_INET: (libc)Internet Namespace.
* PF_LOCAL: (libc)Local Namespace Details.
* PF_UNIX: (libc)Local Namespace Details.
* PIPE_BUF: (libc)Limits for Files.
* pipe: (libc)Creating a Pipe.
* popen: (libc)Pipe to a Subprocess.
* _POSIX2_C_DEV: (libc)System Options.
* _POSIX2_C_VERSION: (libc)Version Supported.
* _POSIX2_FORT_DEV: (libc)System Options.
* _POSIX2_FORT_RUN: (libc)System Options.
* _POSIX2_LOCALEDEF: (libc)System Options.
* _POSIX2_SW_DEV: (libc)System Options.
* _POSIX_CHOWN_RESTRICTED: (libc)Options for Files.
* posix_fallocate64: (libc)Storage Allocation.
* posix_fallocate: (libc)Storage Allocation.
* _POSIX_JOB_CONTROL: (libc)System Options.
* posix_memalign: (libc)Aligned Memory Blocks.
* _POSIX_NO_TRUNC: (libc)Options for Files.
* _POSIX_SAVED_IDS: (libc)System Options.
* _POSIX_VDISABLE: (libc)Options for Files.
* _POSIX_VERSION: (libc)Version Supported.
* pow10f: (libc)Exponents and Logarithms.
* pow10: (libc)Exponents and Logarithms.
* pow10l: (libc)Exponents and Logarithms.
* powf: (libc)Exponents and Logarithms.
* pow: (libc)Exponents and Logarithms.
* powl: (libc)Exponents and Logarithms.
* __ppc_get_timebase_freq: (libc)PowerPC.
* __ppc_get_timebase: (libc)PowerPC.
* __ppc_mdoio: (libc)PowerPC.
* __ppc_mdoom: (libc)PowerPC.
* __ppc_set_ppr_low: (libc)PowerPC.
* __ppc_set_ppr_med_high: (libc)PowerPC.
* __ppc_set_ppr_med: (libc)PowerPC.
* __ppc_set_ppr_med_low: (libc)PowerPC.
* __ppc_set_ppr_very_low: (libc)PowerPC.
* __ppc_yield: (libc)PowerPC.
* pread64: (libc)I/O Primitives.
* pread: (libc)I/O Primitives.
* printf: (libc)Formatted Output Functions.
* printf_size_info: (libc)Predefined Printf Handlers.
* printf_size: (libc)Predefined Printf Handlers.
* psignal: (libc)Signal Messages.
* pthread_getattr_default_np: (libc)Default Thread Attributes.
* pthread_getspecific: (libc)Thread-specific Data.
* pthread_key_create: (libc)Thread-specific Data.
* pthread_key_delete: (libc)Thread-specific Data.
* pthread_setattr_default_np: (libc)Default Thread Attributes.
* pthread_setspecific: (libc)Thread-specific Data.
* P_tmpdir: (libc)Temporary Files.
* ptsname: (libc)Allocation.
* ptsname_r: (libc)Allocation.
* putchar: (libc)Simple Output.
* putchar_unlocked: (libc)Simple Output.
* putc: (libc)Simple Output.
* putc_unlocked: (libc)Simple Output.
* putenv: (libc)Environment Access.
* putpwent: (libc)Writing a User Entry.
* puts: (libc)Simple Output.
* pututline: (libc)Manipulating the Database.
* pututxline: (libc)XPG Functions.
* putwchar: (libc)Simple Output.
* putwchar_unlocked: (libc)Simple Output.
* putwc: (libc)Simple Output.
* putwc_unlocked: (libc)Simple Output.
* putw: (libc)Simple Output.
* pwrite64: (libc)I/O Primitives.
* pwrite: (libc)I/O Primitives.
* qecvt: (libc)System V Number Conversion.
* qecvt_r: (libc)System V Number Conversion.
* qfcvt: (libc)System V Number Conversion.
* qfcvt_r: (libc)System V Number Conversion.
* qgcvt: (libc)System V Number Conversion.
* qsort: (libc)Array Sort Function.
* raise: (libc)Signaling Yourself.
* rand: (libc)ISO Random.
* RAND_MAX: (libc)ISO Random.
* random: (libc)BSD Random.
* random_r: (libc)BSD Random.
* rand_r: (libc)ISO Random.
* rawmemchr: (libc)Search Functions.
* readdir64: (libc)Reading/Closing Directory.
* readdir64_r: (libc)Reading/Closing Directory.
* readdir: (libc)Reading/Closing Directory.
* readdir_r: (libc)Reading/Closing Directory.
* read: (libc)I/O Primitives.
* readlink: (libc)Symbolic Links.
* readv: (libc)Scatter-Gather.
* realloc: (libc)Changing Block Size.
* realpath: (libc)Symbolic Links.
* recvfrom: (libc)Receiving Datagrams.
* recv: (libc)Receiving Data.
* recvmsg: (libc)Receiving Datagrams.
* RE_DUP_MAX: (libc)General Limits.
* regcomp: (libc)POSIX Regexp Compilation.
* regerror: (libc)Regexp Cleanup.
* regexec: (libc)Matching POSIX Regexps.
* regfree: (libc)Regexp Cleanup.
* register_printf_function: (libc)Registering New Conversions.
* remainderf: (libc)Remainder Functions.
* remainder: (libc)Remainder Functions.
* remainderl: (libc)Remainder Functions.
* remove: (libc)Deleting Files.
* rename: (libc)Renaming Files.
* rewinddir: (libc)Random Access Directory.
* rewind: (libc)File Positioning.
* rindex: (libc)Search Functions.
* rintf: (libc)Rounding Functions.
* rint: (libc)Rounding Functions.
* rintl: (libc)Rounding Functions.
* RLIM_INFINITY: (libc)Limits on Resources.
* rmdir: (libc)Deleting Files.
* R_OK: (libc)Testing File Access.
* roundevenf: (libc)Rounding Functions.
* roundeven: (libc)Rounding Functions.
* roundevenl: (libc)Rounding Functions.
* roundf: (libc)Rounding Functions.
* round: (libc)Rounding Functions.
* roundl: (libc)Rounding Functions.
* rpmatch: (libc)Yes-or-No Questions.
* SA_NOCLDSTOP: (libc)Flags for Sigaction.
* SA_ONSTACK: (libc)Flags for Sigaction.
* SA_RESTART: (libc)Flags for Sigaction.
* sbrk: (libc)Resizing the Data Segment.
* scalbf: (libc)Normalization Functions.
* scalb: (libc)Normalization Functions.
* scalbl: (libc)Normalization Functions.
* scalblnf: (libc)Normalization Functions.
* scalbln: (libc)Normalization Functions.
* scalblnl: (libc)Normalization Functions.
* scalbnf: (libc)Normalization Functions.
* scalbn: (libc)Normalization Functions.
* scalbnl: (libc)Normalization Functions.
* scandir64: (libc)Scanning Directory Content.
* scandir: (libc)Scanning Directory Content.
* scanf: (libc)Formatted Input Functions.
* sched_getaffinity: (libc)CPU Affinity.
* sched_getparam: (libc)Basic Scheduling Functions.
* sched_get_priority_max: (libc)Basic Scheduling Functions.
* sched_get_priority_min: (libc)Basic Scheduling Functions.
* sched_getscheduler: (libc)Basic Scheduling Functions.
* sched_rr_get_interval: (libc)Basic Scheduling Functions.
* sched_setaffinity: (libc)CPU Affinity.
* sched_setparam: (libc)Basic Scheduling Functions.
* sched_setscheduler: (libc)Basic Scheduling Functions.
* sched_yield: (libc)Basic Scheduling Functions.
* secure_getenv: (libc)Environment Access.
* seed48: (libc)SVID Random.
* seed48_r: (libc)SVID Random.
* SEEK_CUR: (libc)File Positioning.
* seekdir: (libc)Random Access Directory.
* SEEK_END: (libc)File Positioning.
* SEEK_SET: (libc)File Positioning.
* select: (libc)Waiting for I/O.
* sem_close: (libc)Semaphores.
* semctl: (libc)Semaphores.
* sem_destroy: (libc)Semaphores.
* semget: (libc)Semaphores.
* sem_getvalue: (libc)Semaphores.
* sem_init: (libc)Semaphores.
* sem_open: (libc)Semaphores.
* semop: (libc)Semaphores.
* sem_post: (libc)Semaphores.
* semtimedop: (libc)Semaphores.
* sem_timedwait: (libc)Semaphores.
* sem_trywait: (libc)Semaphores.
* sem_unlink: (libc)Semaphores.
* sem_wait: (libc)Semaphores.
* send: (libc)Sending Data.
* sendmsg: (libc)Receiving Datagrams.
* sendto: (libc)Sending Datagrams.
* setbuffer: (libc)Controlling Buffering.
* setbuf: (libc)Controlling Buffering.
* setcontext: (libc)System V contexts.
* setdomainname: (libc)Host Identification.
* setegid: (libc)Setting Groups.
* setenv: (libc)Environment Access.
* seteuid: (libc)Setting User ID.
* setfsent: (libc)fstab.
* setgid: (libc)Setting Groups.
* setgrent: (libc)Scanning All Groups.
* setgroups: (libc)Setting Groups.
* sethostent: (libc)Host Names.
* sethostid: (libc)Host Identification.
* sethostname: (libc)Host Identification.
* setitimer: (libc)Setting an Alarm.
* setjmp: (libc)Non-Local Details.
* setkey: (libc)DES Encryption.
* setkey_r: (libc)DES Encryption.
* setlinebuf: (libc)Controlling Buffering.
* setlocale: (libc)Setting the Locale.
* setlogmask: (libc)setlogmask.
* setmntent: (libc)mtab.
* setnetent: (libc)Networks Database.
* setnetgrent: (libc)Lookup Netgroup.
* setpayloadf: (libc)FP Bit Twiddling.
* setpayload: (libc)FP Bit Twiddling.
* setpayloadl: (libc)FP Bit Twiddling.
* setpayloadsigf: (libc)FP Bit Twiddling.
* setpayloadsig: (libc)FP Bit Twiddling.
* setpayloadsigl: (libc)FP Bit Twiddling.
* setpgid: (libc)Process Group Functions.
* setpgrp: (libc)Process Group Functions.
* setpriority: (libc)Traditional Scheduling Functions.
* setprotoent: (libc)Protocols Database.
* setpwent: (libc)Scanning All Users.
* setregid: (libc)Setting Groups.
* setreuid: (libc)Setting User ID.
* setrlimit64: (libc)Limits on Resources.
* setrlimit: (libc)Limits on Resources.
* setservent: (libc)Services Database.
* setsid: (libc)Process Group Functions.
* setsockopt: (libc)Socket Option Functions.
* setstate: (libc)BSD Random.
* setstate_r: (libc)BSD Random.
* settimeofday: (libc)High-Resolution Calendar.
* setuid: (libc)Setting User ID.
* setutent: (libc)Manipulating the Database.
* setutxent: (libc)XPG Functions.
* setvbuf: (libc)Controlling Buffering.
* shm_open: (libc)Memory-mapped I/O.
* shm_unlink: (libc)Memory-mapped I/O.
* shutdown: (libc)Closing a Socket.
* S_IFMT: (libc)Testing File Type.
* SIGABRT: (libc)Program Error Signals.
* sigaction: (libc)Advanced Signal Handling.
* sigaddset: (libc)Signal Sets.
* SIGALRM: (libc)Alarm Signals.
* sigaltstack: (libc)Signal Stack.
* sigblock: (libc)BSD Signal Handling.
* SIGBUS: (libc)Program Error Signals.
* SIGCHLD: (libc)Job Control Signals.
* SIGCLD: (libc)Job Control Signals.
* SIGCONT: (libc)Job Control Signals.
* sigdelset: (libc)Signal Sets.
* sigemptyset: (libc)Signal Sets.
* SIGEMT: (libc)Program Error Signals.
* SIG_ERR: (libc)Basic Signal Handling.
* sigfillset: (libc)Signal Sets.
* SIGFPE: (libc)Program Error Signals.
* SIGHUP: (libc)Termination Signals.
* SIGILL: (libc)Program Error Signals.
* SIGINFO: (libc)Miscellaneous Signals.
* siginterrupt: (libc)BSD Signal Handling.
* SIGINT: (libc)Termination Signals.
* SIGIO: (libc)Asynchronous I/O Signals.
* SIGIOT: (libc)Program Error Signals.
* sigismember: (libc)Signal Sets.
* SIGKILL: (libc)Termination Signals.
* siglongjmp: (libc)Non-Local Exits and Signals.
* SIGLOST: (libc)Operation Error Signals.
* sigmask: (libc)BSD Signal Handling.
* signal: (libc)Basic Signal Handling.
* signbit: (libc)FP Bit Twiddling.
* significandf: (libc)Normalization Functions.
* significand: (libc)Normalization Functions.
* significandl: (libc)Normalization Functions.
* sigpause: (libc)BSD Signal Handling.
* sigpending: (libc)Checking for Pending Signals.
* SIGPIPE: (libc)Operation Error Signals.
* SIGPOLL: (libc)Asynchronous I/O Signals.
* sigprocmask: (libc)Process Signal Mask.
* SIGPROF: (libc)Alarm Signals.
* SIGQUIT: (libc)Termination Signals.
* SIGSEGV: (libc)Program Error Signals.
* sigsetjmp: (libc)Non-Local Exits and Signals.
* sigsetmask: (libc)BSD Signal Handling.
* sigstack: (libc)Signal Stack.
* SIGSTOP: (libc)Job Control Signals.
* sigsuspend: (libc)Sigsuspend.
* SIGSYS: (libc)Program Error Signals.
* SIGTERM: (libc)Termination Signals.
* SIGTRAP: (libc)Program Error Signals.
* SIGTSTP: (libc)Job Control Signals.
* SIGTTIN: (libc)Job Control Signals.
* SIGTTOU: (libc)Job Control Signals.
* SIGURG: (libc)Asynchronous I/O Signals.
* SIGUSR1: (libc)Miscellaneous Signals.
* SIGUSR2: (libc)Miscellaneous Signals.
* SIGVTALRM: (libc)Alarm Signals.
* SIGWINCH: (libc)Miscellaneous Signals.
* SIGXCPU: (libc)Operation Error Signals.
* SIGXFSZ: (libc)Operation Error Signals.
* sincosf: (libc)Trig Functions.
* sincos: (libc)Trig Functions.
* sincosl: (libc)Trig Functions.
* sinf: (libc)Trig Functions.
* sinhf: (libc)Hyperbolic Functions.
* sinh: (libc)Hyperbolic Functions.
* sinhl: (libc)Hyperbolic Functions.
* sin: (libc)Trig Functions.
* sinl: (libc)Trig Functions.
* S_ISBLK: (libc)Testing File Type.
* S_ISCHR: (libc)Testing File Type.
* S_ISDIR: (libc)Testing File Type.
* S_ISFIFO: (libc)Testing File Type.
* S_ISLNK: (libc)Testing File Type.
* S_ISREG: (libc)Testing File Type.
* S_ISSOCK: (libc)Testing File Type.
* sleep: (libc)Sleeping.
* SNANF: (libc)Infinity and NaN.
* SNAN: (libc)Infinity and NaN.
* SNANL: (libc)Infinity and NaN.
* snprintf: (libc)Formatted Output Functions.
* SOCK_DGRAM: (libc)Communication Styles.
* socket: (libc)Creating a Socket.
* socketpair: (libc)Socket Pairs.
* SOCK_RAW: (libc)Communication Styles.
* SOCK_RDM: (libc)Communication Styles.
* SOCK_SEQPACKET: (libc)Communication Styles.
* SOCK_STREAM: (libc)Communication Styles.
* SOL_SOCKET: (libc)Socket-Level Options.
* sprintf: (libc)Formatted Output Functions.
* sqrtf: (libc)Exponents and Logarithms.
* sqrt: (libc)Exponents and Logarithms.
* sqrtl: (libc)Exponents and Logarithms.
* srand48: (libc)SVID Random.
* srand48_r: (libc)SVID Random.
* srand: (libc)ISO Random.
* srandom: (libc)BSD Random.
* srandom_r: (libc)BSD Random.
* sscanf: (libc)Formatted Input Functions.
* ssignal: (libc)Basic Signal Handling.
* SSIZE_MAX: (libc)General Limits.
* stat64: (libc)Reading Attributes.
* stat: (libc)Reading Attributes.
* stime: (libc)Simple Calendar Time.
* stpcpy: (libc)Copying Strings and Arrays.
* stpncpy: (libc)Truncating Strings.
* strcasecmp: (libc)String/Array Comparison.
* strcasestr: (libc)Search Functions.
* strcat: (libc)Concatenating Strings.
* strchr: (libc)Search Functions.
* strchrnul: (libc)Search Functions.
* strcmp: (libc)String/Array Comparison.
* strcoll: (libc)Collation Functions.
* strcpy: (libc)Copying Strings and Arrays.
* strcspn: (libc)Search Functions.
* strdupa: (libc)Copying Strings and Arrays.
* strdup: (libc)Copying Strings and Arrays.
* STREAM_MAX: (libc)General Limits.
* strerror: (libc)Error Messages.
* strerror_r: (libc)Error Messages.
* strfmon: (libc)Formatting Numbers.
* strfromd: (libc)Printing of Floats.
* strfromf: (libc)Printing of Floats.
* strfroml: (libc)Printing of Floats.
* strfry: (libc)strfry.
* strftime: (libc)Formatting Calendar Time.
* strlen: (libc)String Length.
* strncasecmp: (libc)String/Array Comparison.
* strncat: (libc)Truncating Strings.
* strncmp: (libc)String/Array Comparison.
* strncpy: (libc)Truncating Strings.
* strndupa: (libc)Truncating Strings.
* strndup: (libc)Truncating Strings.
* strnlen: (libc)String Length.
* strpbrk: (libc)Search Functions.
* strptime: (libc)Low-Level Time String Parsing.
* strrchr: (libc)Search Functions.
* strsep: (libc)Finding Tokens in a String.
* strsignal: (libc)Signal Messages.
* strspn: (libc)Search Functions.
* strstr: (libc)Search Functions.
* strtod: (libc)Parsing of Floats.
* strtof: (libc)Parsing of Floats.
* strtoimax: (libc)Parsing of Integers.
* strtok: (libc)Finding Tokens in a String.
* strtok_r: (libc)Finding Tokens in a String.
* strtold: (libc)Parsing of Floats.
* strtol: (libc)Parsing of Integers.
* strtoll: (libc)Parsing of Integers.
* strtoq: (libc)Parsing of Integers.
* strtoul: (libc)Parsing of Integers.
* strtoull: (libc)Parsing of Integers.
* strtoumax: (libc)Parsing of Integers.
* strtouq: (libc)Parsing of Integers.
* strverscmp: (libc)String/Array Comparison.
* strxfrm: (libc)Collation Functions.
* stty: (libc)BSD Terminal Modes.
* S_TYPEISMQ: (libc)Testing File Type.
* S_TYPEISSEM: (libc)Testing File Type.
* S_TYPEISSHM: (libc)Testing File Type.
* SUN_LEN: (libc)Local Namespace Details.
* swapcontext: (libc)System V contexts.
* swprintf: (libc)Formatted Output Functions.
* swscanf: (libc)Formatted Input Functions.
* symlink: (libc)Symbolic Links.
* sync: (libc)Synchronizing I/O.
* syscall: (libc)System Calls.
* sysconf: (libc)Sysconf Definition.
* sysctl: (libc)System Parameters.
* syslog: (libc)syslog; vsyslog.
* system: (libc)Running a Command.
* sysv_signal: (libc)Basic Signal Handling.
* tanf: (libc)Trig Functions.
* tanhf: (libc)Hyperbolic Functions.
* tanh: (libc)Hyperbolic Functions.
* tanhl: (libc)Hyperbolic Functions.
* tan: (libc)Trig Functions.
* tanl: (libc)Trig Functions.
* tcdrain: (libc)Line Control.
* tcflow: (libc)Line Control.
* tcflush: (libc)Line Control.
* tcgetattr: (libc)Mode Functions.
* tcgetpgrp: (libc)Terminal Access Functions.
* tcgetsid: (libc)Terminal Access Functions.
* tcsendbreak: (libc)Line Control.
* tcsetattr: (libc)Mode Functions.
* tcsetpgrp: (libc)Terminal Access Functions.
* tdelete: (libc)Tree Search Function.
* tdestroy: (libc)Tree Search Function.
* telldir: (libc)Random Access Directory.
* tempnam: (libc)Temporary Files.
* textdomain: (libc)Locating gettext catalog.
* tfind: (libc)Tree Search Function.
* tgammaf: (libc)Special Functions.
* tgamma: (libc)Special Functions.
* tgammal: (libc)Special Functions.
* timegm: (libc)Broken-down Time.
* time: (libc)Simple Calendar Time.
* timelocal: (libc)Broken-down Time.
* times: (libc)Processor Time.
* tmpfile64: (libc)Temporary Files.
* tmpfile: (libc)Temporary Files.
* TMP_MAX: (libc)Temporary Files.
* tmpnam: (libc)Temporary Files.
* tmpnam_r: (libc)Temporary Files.
* toascii: (libc)Case Conversion.
* _tolower: (libc)Case Conversion.
* tolower: (libc)Case Conversion.
* TOSTOP: (libc)Local Modes.
* totalorderf: (libc)FP Comparison Functions.
* totalorder: (libc)FP Comparison Functions.
* totalorderl: (libc)FP Comparison Functions.
* totalordermagf: (libc)FP Comparison Functions.
* totalordermag: (libc)FP Comparison Functions.
* totalordermagl: (libc)FP Comparison Functions.
* _toupper: (libc)Case Conversion.
* toupper: (libc)Case Conversion.
* towctrans: (libc)Wide Character Case Conversion.
* towlower: (libc)Wide Character Case Conversion.
* towupper: (libc)Wide Character Case Conversion.
* truncate64: (libc)File Size.
* truncate: (libc)File Size.
* truncf: (libc)Rounding Functions.
* trunc: (libc)Rounding Functions.
* truncl: (libc)Rounding Functions.
* tsearch: (libc)Tree Search Function.
* ttyname: (libc)Is It a Terminal.
* ttyname_r: (libc)Is It a Terminal.
* twalk: (libc)Tree Search Function.
* TZNAME_MAX: (libc)General Limits.
* tzset: (libc)Time Zone Functions.
* ufromfpf: (libc)Rounding Functions.
* ufromfp: (libc)Rounding Functions.
* ufromfpl: (libc)Rounding Functions.
* ufromfpxf: (libc)Rounding Functions.
* ufromfpx: (libc)Rounding Functions.
* ufromfpxl: (libc)Rounding Functions.
* ulimit: (libc)Limits on Resources.
* umask: (libc)Setting Permissions.
* umount2: (libc)Mount-Unmount-Remount.
* umount: (libc)Mount-Unmount-Remount.
* uname: (libc)Platform Type.
* ungetc: (libc)How Unread.
* ungetwc: (libc)How Unread.
* unlink: (libc)Deleting Files.
* unlockpt: (libc)Allocation.
* unsetenv: (libc)Environment Access.
* updwtmp: (libc)Manipulating the Database.
* utime: (libc)File Times.
* utimes: (libc)File Times.
* utmpname: (libc)Manipulating the Database.
* utmpxname: (libc)XPG Functions.
* va_arg: (libc)Argument Macros.
* __va_copy: (libc)Argument Macros.
* va_copy: (libc)Argument Macros.
* va_end: (libc)Argument Macros.
* valloc: (libc)Aligned Memory Blocks.
* vasprintf: (libc)Variable Arguments Output.
* va_start: (libc)Argument Macros.
* VDISCARD: (libc)Other Special.
* VDSUSP: (libc)Signal Characters.
* VEOF: (libc)Editing Characters.
* VEOL2: (libc)Editing Characters.
* VEOL: (libc)Editing Characters.
* VERASE: (libc)Editing Characters.
* verr: (libc)Error Messages.
* verrx: (libc)Error Messages.
* versionsort64: (libc)Scanning Directory Content.
* versionsort: (libc)Scanning Directory Content.
* vfork: (libc)Creating a Process.
* vfprintf: (libc)Variable Arguments Output.
* vfscanf: (libc)Variable Arguments Input.
* vfwprintf: (libc)Variable Arguments Output.
* vfwscanf: (libc)Variable Arguments Input.
* VINTR: (libc)Signal Characters.
* VKILL: (libc)Editing Characters.
* vlimit: (libc)Limits on Resources.
* VLNEXT: (libc)Other Special.
* VMIN: (libc)Noncanonical Input.
* vprintf: (libc)Variable Arguments Output.
* VQUIT: (libc)Signal Characters.
* VREPRINT: (libc)Editing Characters.
* vscanf: (libc)Variable Arguments Input.
* vsnprintf: (libc)Variable Arguments Output.
* vsprintf: (libc)Variable Arguments Output.
* vsscanf: (libc)Variable Arguments Input.
* VSTART: (libc)Start/Stop Characters.
* VSTATUS: (libc)Other Special.
* VSTOP: (libc)Start/Stop Characters.
* VSUSP: (libc)Signal Characters.
* vswprintf: (libc)Variable Arguments Output.
* vswscanf: (libc)Variable Arguments Input.
* vsyslog: (libc)syslog; vsyslog.
* VTIME: (libc)Noncanonical Input.
* vtimes: (libc)Resource Usage.
* vwarn: (libc)Error Messages.
* vwarnx: (libc)Error Messages.
* VWERASE: (libc)Editing Characters.
* vwprintf: (libc)Variable Arguments Output.
* vwscanf: (libc)Variable Arguments Input.
* wait3: (libc)BSD Wait Functions.
* wait4: (libc)Process Completion.
* wait: (libc)Process Completion.
* waitpid: (libc)Process Completion.
* warn: (libc)Error Messages.
* warnx: (libc)Error Messages.
* WCHAR_MAX: (libc)Extended Char Intro.
* WCHAR_MIN: (libc)Extended Char Intro.
* WCOREDUMP: (libc)Process Completion Status.
* wcpcpy: (libc)Copying Strings and Arrays.
* wcpncpy: (libc)Truncating Strings.
* wcrtomb: (libc)Converting a Character.
* wcscasecmp: (libc)String/Array Comparison.
* wcscat: (libc)Concatenating Strings.
* wcschr: (libc)Search Functions.
* wcschrnul: (libc)Search Functions.
* wcscmp: (libc)String/Array Comparison.
* wcscoll: (libc)Collation Functions.
* wcscpy: (libc)Copying Strings and Arrays.
* wcscspn: (libc)Search Functions.
* wcsdup: (libc)Copying Strings and Arrays.
* wcsftime: (libc)Formatting Calendar Time.
* wcslen: (libc)String Length.
* wcsncasecmp: (libc)String/Array Comparison.
* wcsncat: (libc)Truncating Strings.
* wcsncmp: (libc)String/Array Comparison.
* wcsncpy: (libc)Truncating Strings.
* wcsnlen: (libc)String Length.
* wcsnrtombs: (libc)Converting Strings.
* wcspbrk: (libc)Search Functions.
* wcsrchr: (libc)Search Functions.
* wcsrtombs: (libc)Converting Strings.
* wcsspn: (libc)Search Functions.
* wcsstr: (libc)Search Functions.
* wcstod: (libc)Parsing of Floats.
* wcstof: (libc)Parsing of Floats.
* wcstoimax: (libc)Parsing of Integers.
* wcstok: (libc)Finding Tokens in a String.
* wcstold: (libc)Parsing of Floats.
* wcstol: (libc)Parsing of Integers.
* wcstoll: (libc)Parsing of Integers.
* wcstombs: (libc)Non-reentrant String Conversion.
* wcstoq: (libc)Parsing of Integers.
* wcstoul: (libc)Parsing of Integers.
* wcstoull: (libc)Parsing of Integers.
* wcstoumax: (libc)Parsing of Integers.
* wcstouq: (libc)Parsing of Integers.
* wcswcs: (libc)Search Functions.
* wcsxfrm: (libc)Collation Functions.
* wctob: (libc)Converting a Character.
* wctomb: (libc)Non-reentrant Character Conversion.
* wctrans: (libc)Wide Character Case Conversion.
* wctype: (libc)Classification of Wide Characters.
* WEOF: (libc)EOF and Errors.
* WEOF: (libc)Extended Char Intro.
* WEXITSTATUS: (libc)Process Completion Status.
* WIFEXITED: (libc)Process Completion Status.
* WIFSIGNALED: (libc)Process Completion Status.
* WIFSTOPPED: (libc)Process Completion Status.
* wmemchr: (libc)Search Functions.
* wmemcmp: (libc)String/Array Comparison.
* wmemcpy: (libc)Copying Strings and Arrays.
* wmemmove: (libc)Copying Strings and Arrays.
* wmempcpy: (libc)Copying Strings and Arrays.
* wmemset: (libc)Copying Strings and Arrays.
* W_OK: (libc)Testing File Access.
* wordexp: (libc)Calling Wordexp.
* wordfree: (libc)Calling Wordexp.
* wprintf: (libc)Formatted Output Functions.
* write: (libc)I/O Primitives.
* writev: (libc)Scatter-Gather.
* wscanf: (libc)Formatted Input Functions.
* WSTOPSIG: (libc)Process Completion Status.
* WTERMSIG: (libc)Process Completion Status.
* X_OK: (libc)Testing File Access.
* y0f: (libc)Special Functions.
* y0: (libc)Special Functions.
* y0l: (libc)Special Functions.
* y1f: (libc)Special Functions.
* y1: (libc)Special Functions.
* y1l: (libc)Special Functions.
* ynf: (libc)Special Functions.
* yn: (libc)Special Functions.
* ynl: (libc)Special Functions.
END-INFO-DIR-ENTRY


File: libc.info,  Node: Installation,  Next: Maintenance,  Prev: Library Summary,  Up: Top

Appendix C Installing the GNU C Library
***************************************

Before you do anything else, you should read the FAQ at
<http://sourceware.org/glibc/wiki/FAQ>.  It answers common questions and
describes problems you may experience with compilation and installation.

   Features can be added to the GNU C Library via "add-on" bundles.
These are separate tar files, which you unpack into the top level of the
source tree.  Then you give ‘configure’ the ‘--enable-add-ons’ option to
activate them, and they will be compiled into the library.

   You will need recent versions of several GNU tools: definitely GCC
and GNU Make, and possibly others.  *Note Tools for Compilation::,
below.

* Menu:

* Configuring and compiling::   How to compile and test GNU libc.
* Running make install::        How to install it once you’ve got it
 compiled.
* Tools for Compilation::       You’ll need these first.
* Linux::                       Specific advice for GNU/Linux systems.
* Reporting Bugs::              So they’ll get fixed.


File: libc.info,  Node: Configuring and compiling,  Next: Running make install,  Up: Installation

C.1 Configuring and compiling the GNU C Library
===============================================

The GNU C Library cannot be compiled in the source directory.  You must
build it in a separate build directory.  For example, if you have
unpacked the GNU C Library sources in ‘/src/gnu/glibc-VERSION’, create a
directory ‘/src/gnu/glibc-build’ to put the object files in.  This
allows removing the whole build directory in case an error occurs, which
is the safest way to get a fresh start and should always be done.

   From your object directory, run the shell script ‘configure’ located
at the top level of the source tree.  In the scenario above, you’d type

     $ ../glibc-VERSION/configure ARGS…

   Please note that even though you’re building in a separate build
directory, the compilation may need to create or modify files and
directories in the source directory.

‘configure’ takes many options, but the only one that is usually
mandatory is ‘--prefix’.  This option tells ‘configure’ where you want
the GNU C Library installed.  This defaults to ‘/usr/local’, but the
normal setting to install as the standard system library is
‘--prefix=/usr’ for GNU/Linux systems and ‘--prefix=’ (an empty prefix)
for GNU/Hurd systems.

   It may also be useful to set the CC and CFLAGS variables in the
environment when running ‘configure’.  CC selects the C compiler that
will be used, and CFLAGS sets optimization options for the compiler.

   The following list describes all of the available options for
‘configure’:

‘--prefix=DIRECTORY’
     Install machine-independent data files in subdirectories of
     ‘DIRECTORY’.  The default is to install in ‘/usr/local’.

‘--exec-prefix=DIRECTORY’
     Install the library and other machine-dependent files in
     subdirectories of ‘DIRECTORY’.  The default is to the ‘--prefix’
     directory if that option is specified, or ‘/usr/local’ otherwise.

‘--with-headers=DIRECTORY’
     Look for kernel header files in DIRECTORY, not ‘/usr/include’.  The
     GNU C Library needs information from the kernel’s header files
     describing the interface to the kernel.  The GNU C Library will
     normally look in ‘/usr/include’ for them, but if you specify this
     option, it will look in DIRECTORY instead.

     This option is primarily of use on a system where the headers in
     ‘/usr/include’ come from an older version of the GNU C Library.
     Conflicts can occasionally happen in this case.  You can also use
     this option if you want to compile the GNU C Library with a newer
     set of kernel headers than the ones found in ‘/usr/include’.

‘--enable-add-ons[=LIST]’
     Specify add-on packages to include in the build.  If this option is
     specified with no list, it enables all the add-on packages it finds
     in the main source directory; this is the default behavior.  You
     may specify an explicit list of add-ons to use in LIST, separated
     by spaces or commas (if you use spaces, remember to quote them from
     the shell).  Each add-on in LIST can be an absolute directory name
     or can be a directory name relative to the main source directory,
     or relative to the build directory (that is, the current working
     directory).  For example,
     ‘--enable-add-ons=nptl,../glibc-libidn-VERSION’.

‘--enable-kernel=VERSION’
     This option is currently only useful on GNU/Linux systems.  The
     VERSION parameter should have the form X.Y.Z and describes the
     smallest version of the Linux kernel the generated library is
     expected to support.  The higher the VERSION number is, the less
     compatibility code is added, and the faster the code gets.

‘--with-binutils=DIRECTORY’
     Use the binutils (assembler and linker) in ‘DIRECTORY’, not the
     ones the C compiler would default to.  You can use this option if
     the default binutils on your system cannot deal with all the
     constructs in the GNU C Library.  In that case, ‘configure’ will
     detect the problem and suppress these constructs, so that the
     library will still be usable, but functionality may be lost—for
     example, you can’t build a shared libc with old binutils.

‘--without-fp’
     Use this option if your computer lacks hardware floating-point
     support and your operating system does not emulate an FPU.

‘--disable-shared’
     Don’t build shared libraries even if it is possible.  Not all
     systems support shared libraries; you need ELF support and
     (currently) the GNU linker.

‘--disable-profile’
     Don’t build libraries with profiling information.  You may want to
     use this option if you don’t plan to do profiling.

‘--enable-static-nss’
     Compile static versions of the NSS (Name Service Switch) libraries.
     This is not recommended because it defeats the purpose of NSS; a
     program linked statically with the NSS libraries cannot be
     dynamically reconfigured to use a different name database.

‘--enable-hardcoded-path-in-tests’
     By default, dynamic tests are linked to run with the installed C
     library.  This option hardcodes the newly built C library path in
     dynamic tests so that they can be invoked directly.

‘--disable-timezone-tools’
     By default, timezone related utilities (‘zic’, ‘zdump’, and
     ‘tzselect’) are installed with the GNU C Library.  If you are
     building these independently (e.g.  by using the ‘tzcode’ package),
     then this option will allow disabling the install of these.

     Note that you need to make sure the external tools are kept in sync
     with the versions that the GNU C Library expects as the data
     formats may change over time.  Consult the ‘timezone’ subdirectory
     for more details.

‘--enable-lock-elision=yes’
     Enable lock elision for pthread mutexes by default.

‘--enable-stack-protector’
‘--enable-stack-protector=strong’
‘--enable-stack-protector=all’
     Compile the C library and all other parts of the glibc package
     (including the threading and math libraries, NSS modules, and
     transliteration modules) using the GCC ‘-fstack-protector’,
     ‘-fstack-protector-strong’ or ‘-fstack-protector-all’ options to
     detect stack overruns.  Only the dynamic linker and a small number
     of routines called directly from assembler are excluded from this
     protection.

‘--enable-bind-now’
     Disable lazy binding for installed shared objects.  This provides
     additional security hardening because it enables full RELRO and a
     read-only global offset table (GOT), at the cost of slightly
     increased program load times.

‘--enable-pt_chown’
     The file ‘pt_chown’ is a helper binary for ‘grantpt’ (*note
     Pseudo-Terminals: Allocation.) that is installed setuid root to fix
     up pseudo-terminal ownership.  It is not built by default because
     systems using the Linux kernel are commonly built with the ‘devpts’
     filesystem enabled and mounted at ‘/dev/pts’, which manages
     pseudo-terminal ownership automatically.  By using
     ‘--enable-pt_chown’, you may build ‘pt_chown’ and install it setuid
     and owned by ‘root’.  The use of ‘pt_chown’ introduces additional
     security risks to the system and you should enable it only if you
     understand and accept those risks.

‘--disable-werror’
     By default, the GNU C Library is built with ‘-Werror’.  If you wish
     to build without this option (for example, if building with a newer
     version of GCC than this version of the GNU C Library was tested
     with, so new warnings cause the build with ‘-Werror’ to fail), you
     can configure with ‘--disable-werror’.

‘--disable-mathvec’
     By default for x86_64, the GNU C Library is built with the vector
     math library.  Use this option to disable the vector math library.

‘--enable-tunables’
     Tunables support allows additional library parameters to be
     customized at runtime.  This is an experimental feature and affects
     startup time and is thus disabled by default.  This option can take
     the following values:

     ‘no’
          This is the default if the option is not passed to configure.
          This disables tunables.

     ‘yes’
          This is the default if the option is passed to configure.
          This enables tunables and selects the default frontend
          (currently ‘valstring’).

     ‘valstring’
          This enables tunables and selects the ‘valstring’ frontend for
          tunables.  This frontend allows users to specify tunables as a
          colon-separated list in a single environment variable
          ‘GLIBC_TUNABLES’.

‘--build=BUILD-SYSTEM’
‘--host=HOST-SYSTEM’
     These options are for cross-compiling.  If you specify both options
     and BUILD-SYSTEM is different from HOST-SYSTEM, ‘configure’ will
     prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be
     used on HOST-SYSTEM.  You’ll probably need the ‘--with-headers’
     option too, and you may have to override CONFIGURE’s selection of
     the compiler and/or binutils.

     If you only specify ‘--host’, ‘configure’ will prepare for a native
     compile but use what you specify instead of guessing what your
     system is.  This is most useful to change the CPU submodel.  For
     example, if ‘configure’ guesses your machine as ‘i686-pc-linux-gnu’
     but you want to compile a library for 586es, give
     ‘--host=i586-pc-linux-gnu’ or just ‘--host=i586-linux’ and add the
     appropriate compiler flags (‘-mcpu=i586’ will do the trick) to
     CFLAGS.

     If you specify just ‘--build’, ‘configure’ will get confused.

‘--with-pkgversion=VERSION’
     Specify a description, possibly including a build number or build
     date, of the binaries being built, to be included in ‘--version’
     output from programs installed with the GNU C Library.  For
     example, ‘--with-pkgversion='FooBar GNU/Linux glibc build 123'’.
     The default value is ‘GNU libc’.

‘--with-bugurl=URL’
     Specify the URL that users should visit if they wish to report a
     bug, to be included in ‘--help’ output from programs installed with
     the GNU C Library.  The default value refers to the main
     bug-reporting information for the GNU C Library.

   To build the library and related programs, type ‘make’.  This will
produce a lot of output, some of which may look like errors from ‘make’
but aren’t.  Look for error messages from ‘make’ containing ‘***’.
Those indicate that something is seriously wrong.

   The compilation process can take a long time, depending on the
configuration and the speed of your machine.  Some complex modules may
take a very long time to compile, as much as several minutes on slower
machines.  Do not panic if the compiler appears to hang.

   If you want to run a parallel make, simply pass the ‘-j’ option with
an appropriate numeric parameter to ‘make’.  You need a recent GNU
‘make’ version, though.

   To build and run test programs which exercise some of the library
facilities, type ‘make check’.  If it does not complete successfully, do
not use the built library, and report a bug after verifying that the
problem is not already known.  *Note Reporting Bugs::, for instructions
on reporting bugs.  Note that some of the tests assume they are not
being run by ‘root’.  We recommend you compile and test the GNU C
Library as an unprivileged user.

   Before reporting bugs make sure there is no problem with your system.
The tests (and later installation) use some pre-existing files of the
system such as ‘/etc/passwd’, ‘/etc/nsswitch.conf’ and others.  These
files must all contain correct and sensible content.

   Normally, ‘make check’ will run all the tests before reporting all
problems found and exiting with error status if any problems occurred.
You can specify ‘stop-on-test-failure=y’ when running ‘make check’ to
make the test run stop and exit with an error status immediately when a
failure occurs.

   The GNU C Library pretty printers come with their own set of scripts
for testing, which run together with the rest of the testsuite through
‘make check’.  These scripts require the following tools to run
successfully:

   • Python 2.7.6/3.4.3 or later

     Python is required for running the printers’ test scripts.

   • PExpect 4.0

     The printer tests drive GDB through test programs and compare its
     output to the printers’.  PExpect is used to capture the output of
     GDB, and should be compatible with the Python version in your
     system.

   • GDB 7.8 or later with support for Python 2.7.6/3.4.3 or later

     GDB itself needs to be configured with Python support in order to
     use the pretty printers.  Notice that your system having Python
     available doesn’t imply that GDB supports it, nor that your
     system’s Python and GDB’s have the same version.

If these tools are absent, the printer tests will report themselves as
‘UNSUPPORTED’.  Notice that some of the printer tests require the GNU C
Library to be compiled with debugging symbols.

   To format the ‘GNU C Library Reference Manual’ for printing, type
‘make dvi’.  You need a working TeX installation to do this.  The
distribution builds the on-line formatted version of the manual, as Info
files, as part of the build process.  You can build them manually with
‘make info’.

   The library has a number of special-purpose configuration parameters
which you can find in ‘Makeconfig’.  These can be overwritten with the
file ‘configparms’.  To change them, create a ‘configparms’ in your
build directory and add values as appropriate for your system.  The file
is included and parsed by ‘make’ and has to follow the conventions for
makefiles.

   It is easy to configure the GNU C Library for cross-compilation by
setting a few variables in ‘configparms’.  Set ‘CC’ to the
cross-compiler for the target you configured the library for; it is
important to use this same ‘CC’ value when running ‘configure’, like
this: ‘CC=TARGET-gcc configure TARGET’.  Set ‘BUILD_CC’ to the compiler
to use for programs run on the build system as part of compiling the
library.  You may need to set ‘AR’ to cross-compiling versions of ‘ar’
if the native tools are not configured to work with object files for the
target you configured for.  When cross-compiling the GNU C Library, it
may be tested using ‘make check
test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"’, where SRCDIR
is the absolute directory name for the main source directory and
HOSTNAME is the host name of a system that can run the newly built
binaries of the GNU C Library.  The source and build directories must be
visible at the same locations on both the build system and HOSTNAME.

   In general, when testing the GNU C Library, ‘test-wrapper’ may be set
to the name and arguments of any program to run newly built binaries.
This program must preserve the arguments to the binary being run, its
working directory and the standard input, output and error file
descriptors.  If ‘TEST-WRAPPER env’ will not work to run a program with
environment variables set, then ‘test-wrapper-env’ must be set to a
program that runs a newly built program with environment variable
assignments in effect, those assignments being specified as ‘VAR=VALUE’
before the name of the program to be run.  If multiple assignments to
the same variable are specified, the last assignment specified must take
precedence.  Similarly, if ‘TEST-WRAPPER env -i’ will not work to run a
program with an environment completely empty of variables except those
directly assigned, then ‘test-wrapper-env-only’ must be set; its use has
the same syntax as ‘test-wrapper-env’, the only difference in its
semantics being starting with an empty set of environment variables
rather than the ambient set.


File: libc.info,  Node: Running make install,  Next: Tools for Compilation,  Prev: Configuring and compiling,  Up: Installation

C.2 Installing the C Library
============================

To install the library and its header files, and the Info files of the
manual, type ‘make install’.  This will build things, if necessary,
before installing them; however, you should still compile everything
first.  If you are installing the GNU C Library as your primary C
library, we recommend that you shut the system down to single-user mode
first, and reboot afterward.  This minimizes the risk of breaking things
when the library changes out from underneath.

   ‘make install’ will do the entire job of upgrading from a previous
installation of the GNU C Library version 2.x.  There may sometimes be
headers left behind from the previous installation, but those are
generally harmless.  If you want to avoid leaving headers behind you can
do things in the following order.

   You must first build the library (‘make’), optionally check it (‘make
check’), switch the include directories and then install (‘make
install’).  The steps must be done in this order.  Not moving the
directory before install will result in an unusable mixture of header
files from both libraries, but configuring, building, and checking the
library requires the ability to compile and run programs against the old
library.  The new ‘/usr/include’, after switching the include
directories and before installing the library should contain the Linux
headers, but nothing else.  If you do this, you will need to restore any
headers from libraries other than the GNU C Library yourself after
installing the library.

   You can install the GNU C Library somewhere other than where you
configured it to go by setting the ‘DESTDIR’ GNU standard make variable
on the command line for ‘make install’.  The value of this variable is
prepended to all the paths for installation.  This is useful when
setting up a chroot environment or preparing a binary distribution.  The
directory should be specified with an absolute file name.  Installing
with the ‘prefix’ and ‘exec_prefix’ GNU standard make variables set is
not supported.

   The GNU C Library includes a daemon called ‘nscd’, which you may or
may not want to run.  ‘nscd’ caches name service lookups; it can
dramatically improve performance with NIS+, and may help with DNS as
well.

   One auxiliary program, ‘/usr/libexec/pt_chown’, is installed setuid
‘root’ if the ‘--enable-pt_chown’ configuration option is used.  This
program is invoked by the ‘grantpt’ function; it sets the permissions on
a pseudoterminal so it can be used by the calling process.  If you are
using a Linux kernel with the ‘devpts’ filesystem enabled and mounted at
‘/dev/pts’, you don’t need this program.

   After installation you might want to configure the timezone and
locale installation of your system.  The GNU C Library comes with a
locale database which gets configured with ‘localedef’.  For example, to
set up a German locale with name ‘de_DE’, simply issue the command
‘localedef -i de_DE -f ISO-8859-1 de_DE’.  To configure all locales that
are supported by the GNU C Library, you can issue from your build
directory the command ‘make localedata/install-locales’.

   To configure the locally used timezone, set the ‘TZ’ environment
variable.  The script ‘tzselect’ helps you to select the right value.
As an example, for Germany, ‘tzselect’ would tell you to use
‘TZ='Europe/Berlin'’.  For a system wide installation (the given paths
are for an installation with ‘--prefix=/usr’), link the timezone file
which is in ‘/usr/share/zoneinfo’ to the file ‘/etc/localtime’.  For
Germany, you might execute ‘ln -s /usr/share/zoneinfo/Europe/Berlin
/etc/localtime’.


File: libc.info,  Node: Tools for Compilation,  Next: Linux,  Prev: Running make install,  Up: Installation

C.3 Recommended Tools for Compilation
=====================================

We recommend installing the following GNU tools before attempting to
build the GNU C Library:

   • GNU ‘make’ 3.79 or newer

     You need the latest version of GNU ‘make’.  Modifying the GNU C
     Library to work with other ‘make’ programs would be so difficult
     that we recommend you port GNU ‘make’ instead.  *Really.*  We
     recommend GNU ‘make’ version 3.79.  All earlier versions have
     severe bugs or lack features.

   • GCC 4.7 or newer

     GCC 4.7 or higher is required.  In general it is recommended to use
     the newest version of the compiler that is known to work for
     building the GNU C Library, as newer compilers usually produce
     better code.  As of release time, GCC 6.3 is the newest compiler
     verified to work to build the GNU C Library.

     For multi-arch support it is recommended to use a GCC which has
     been built with support for GNU indirect functions.  This ensures
     that correct debugging information is generated for functions
     selected by IFUNC resolvers.  This support can either be enabled by
     configuring GCC with ‘--enable-gnu-indirect-function’, or by
     enabling it by default by setting ‘default_gnu_indirect_function’
     variable for a particular architecture in the GCC source file
     ‘gcc/config.gcc’.

     You can use whatever compiler you like to compile programs that use
     the GNU C Library.

     Check the FAQ for any special compiler issues on particular
     platforms.

   • GNU ‘binutils’ 2.22 or later

     You must use GNU ‘binutils’ (as and ld) to build the GNU C Library.
     No other assembler or linker has the necessary functionality at the
     moment.  As of release time, GNU ‘binutils’ 2.25 is the newest
     verified to work to build the GNU C Library.

   • GNU ‘texinfo’ 4.7 or later

     To correctly translate and install the Texinfo documentation you
     need this version of the ‘texinfo’ package.  Earlier versions do
     not understand all the tags used in the document, and the
     installation mechanism for the info files is not present or works
     differently.  As of release time, ‘texinfo’ 6.0 is the newest
     verified to work to build the GNU C Library.

   • GNU ‘awk’ 3.1.2, or higher

     ‘awk’ is used in several places to generate files.  Some ‘gawk’
     extensions are used, including the ‘asorti’ function, which was
     introduced in version 3.1.2 of ‘gawk’.  As of release time, ‘gawk’
     version 4.1.3 is the newest verified to work to build the GNU C
     Library.

   • Perl 5

     Perl is not required, but it is used if present to test the
     installation.  We may decide to use it elsewhere in the future.

   • GNU ‘sed’ 3.02 or newer

     ‘Sed’ is used in several places to generate files.  Most scripts
     work with any version of ‘sed’.  As of release time, ‘sed’ version
     4.2.2 is the newest verified to work to build the GNU C Library.

If you change any of the ‘configure.ac’ files you will also need

   • GNU ‘autoconf’ 2.69 (exactly)

and if you change any of the message translation files you will need

   • GNU ‘gettext’ 0.10.36 or later

If you wish to regenerate the ‘yacc’ parser code in the ‘intl’
subdirectory you will need

   • GNU ‘bison’ 2.7 or later

You may also need these packages if you upgrade your source tree using
patches, although we try to avoid this.


File: libc.info,  Node: Linux,  Next: Reporting Bugs,  Prev: Tools for Compilation,  Up: Installation

C.4 Specific advice for GNU/Linux systems
=========================================

If you are installing the GNU C Library on GNU/Linux systems, you need
to have the header files from a 3.2 or newer kernel around for
reference.  These headers must be installed using ‘make
headers_install’; the headers present in the kernel source directory are
not suitable for direct use by the GNU C Library.  You do not need to
use that kernel, just have its headers installed where the GNU C Library
can access them, referred to here as INSTALL-DIRECTORY.  The easiest way
to do this is to unpack it in a directory such as
‘/usr/src/linux-VERSION’.  In that directory, run ‘make headers_install
INSTALL_HDR_PATH=INSTALL-DIRECTORY’.  Finally, configure the GNU C
Library with the option ‘--with-headers=INSTALL-DIRECTORY/include’.  Use
the most recent kernel you can get your hands on.  (If you are
cross-compiling the GNU C Library, you need to specify
‘ARCH=ARCHITECTURE’ in the ‘make headers_install’ command, where
ARCHITECTURE is the architecture name used by the Linux kernel, such as
‘x86’ or ‘powerpc’.)

   After installing the GNU C Library, you may need to remove or rename
directories such as ‘/usr/include/linux’ and ‘/usr/include/asm’, and
replace them with copies of directories such as ‘linux’ and ‘asm’ from
‘INSTALL-DIRECTORY/include’.  All directories present in
‘INSTALL-DIRECTORY/include’ should be copied, except that the GNU C
Library provides its own version of ‘/usr/include/scsi’; the files
provided by the kernel should be copied without replacing those provided
by the GNU C Library.  The ‘linux’, ‘asm’ and ‘asm-generic’ directories
are required to compile programs using the GNU C Library; the other
directories describe interfaces to the kernel but are not required if
not compiling programs using those interfaces.  You do not need to copy
kernel headers if you did not specify an alternate kernel header source
using ‘--with-headers’.

   The Filesystem Hierarchy Standard for GNU/Linux systems expects some
components of the GNU C Library installation to be in ‘/lib’ and some in
‘/usr/lib’.  This is handled automatically if you configure the GNU C
Library with ‘--prefix=/usr’.  If you set some other prefix or allow it
to default to ‘/usr/local’, then all the components are installed there.


File: libc.info,  Node: Reporting Bugs,  Prev: Linux,  Up: Installation

C.5 Reporting Bugs
==================

There are probably bugs in the GNU C Library.  There are certainly
errors and omissions in this manual.  If you report them, they will get
fixed.  If you don’t, no one will ever know about them and they will
remain unfixed for all eternity, if not longer.

   It is a good idea to verify that the problem has not already been
reported.  Bugs are documented in two places: The file ‘BUGS’ describes
a number of well known bugs and the central GNU C Library bug tracking
system has a WWW interface at <http://sourceware.org/bugzilla/>.  The
WWW interface gives you access to open and closed reports.  A closed
report normally includes a patch or a hint on solving the problem.

   To report a bug, first you must find it.  With any luck, this will be
the hard part.  Once you’ve found a bug, make sure it’s really a bug.  A
good way to do this is to see if the GNU C Library behaves the same way
some other C library does.  If so, probably you are wrong and the
libraries are right (but not necessarily).  If not, one of the libraries
is probably wrong.  It might not be the GNU C Library.  Many historical
Unix C libraries permit things that we don’t, such as closing a file
twice.

   If you think you have found some way in which the GNU C Library does
not conform to the ISO and POSIX standards (*note Standards and
Portability::), that is definitely a bug.  Report it!

   Once you’re sure you’ve found a bug, try to narrow it down to the
smallest test case that reproduces the problem.  In the case of a C
library, you really only need to narrow it down to one library function
call, if possible.  This should not be too difficult.

   The final step when you have a simple test case is to report the bug.
Do this at <http://www.gnu.org/software/libc/bugs.html>.

   If you are not sure how a function should behave, and this manual
doesn’t tell you, that’s a bug in the manual.  Report that too!  If the
function’s behavior disagrees with the manual, then either the library
or the manual has a bug, so report the disagreement.  If you find any
errors or omissions in this manual, please report them to the bug
database.  If you refer to specific sections of the manual, please
include the section names for easier identification.


File: libc.info,  Node: Maintenance,  Next: Platform,  Prev: Installation,  Up: Top

Appendix D Library Maintenance
******************************

* Menu:

* Source Layout::         How to add new functions or header files
                             to the GNU C Library.
* Porting::               How to port the GNU C Library to
                             a new machine or operating system.


File: libc.info,  Node: Source Layout,  Next: Porting,  Up: Maintenance

D.1 Adding New Functions
========================

The process of building the library is driven by the makefiles, which
make heavy use of special features of GNU ‘make’.  The makefiles are
very complex, and you probably don’t want to try to understand them.
But what they do is fairly straightforward, and only requires that you
define a few variables in the right places.

   The library sources are divided into subdirectories, grouped by
topic.

   The ‘string’ subdirectory has all the string-manipulation functions,
‘math’ has all the mathematical functions, etc.

   Each subdirectory contains a simple makefile, called ‘Makefile’,
which defines a few ‘make’ variables and then includes the global
makefile ‘Rules’ with a line like:

     include ../Rules

The basic variables that a subdirectory makefile defines are:

‘subdir’
     The name of the subdirectory, for example ‘stdio’.  This variable
     *must* be defined.

‘headers’
     The names of the header files in this section of the library, such
     as ‘stdio.h’.

‘routines’
‘aux’
     The names of the modules (source files) in this section of the
     library.  These should be simple names, such as ‘strlen’ (rather
     than complete file names, such as ‘strlen.c’).  Use ‘routines’ for
     modules that define functions in the library, and ‘aux’ for
     auxiliary modules containing things like data definitions.  But the
     values of ‘routines’ and ‘aux’ are just concatenated, so there
     really is no practical difference.

‘tests’
     The names of test programs for this section of the library.  These
     should be simple names, such as ‘tester’ (rather than complete file
     names, such as ‘tester.c’).  ‘make tests’ will build and run all
     the test programs.  If a test program needs input, put the test
     data in a file called ‘TEST-PROGRAM.input’; it will be given to the
     test program on its standard input.  If a test program wants to be
     run with arguments, put the arguments (all on a single line) in a
     file called ‘TEST-PROGRAM.args’.  Test programs should exit with
     zero status when the test passes, and nonzero status when the test
     indicates a bug in the library or error in building.

‘others’
     The names of “other” programs associated with this section of the
     library.  These are programs which are not tests per se, but are
     other small programs included with the library.  They are built by
     ‘make others’.

‘install-lib’
‘install-data’
‘install’
     Files to be installed by ‘make install’.  Files listed in
     ‘install-lib’ are installed in the directory specified by ‘libdir’
     in ‘configparms’ or ‘Makeconfig’ (*note Installation::).  Files
     listed in ‘install-data’ are installed in the directory specified
     by ‘datadir’ in ‘configparms’ or ‘Makeconfig’.  Files listed in
     ‘install’ are installed in the directory specified by ‘bindir’ in
     ‘configparms’ or ‘Makeconfig’.

‘distribute’
     Other files from this subdirectory which should be put into a
     distribution tar file.  You need not list here the makefile itself
     or the source and header files listed in the other standard
     variables.  Only define ‘distribute’ if there are files used in an
     unusual way that should go into the distribution.

‘generated’
     Files which are generated by ‘Makefile’ in this subdirectory.
     These files will be removed by ‘make clean’, and they will never go
     into a distribution.

‘extra-objs’
     Extra object files which are built by ‘Makefile’ in this
     subdirectory.  This should be a list of file names like ‘foo.o’;
     the files will actually be found in whatever directory object files
     are being built in.  These files will be removed by ‘make clean’.
     This variable is used for secondary object files needed to build
     ‘others’ or ‘tests’.

* Menu:

* Platform: Adding Platform-specific.             Adding platform-specific
                                         features.


File: libc.info,  Node: Adding Platform-specific,  Up: Source Layout

D.1.1 Platform-specific types, macros and functions
---------------------------------------------------

It’s sometimes necessary to provide nonstandard, platform-specific
features to developers.  The C library is traditionally the lowest
library layer, so it makes sense for it to provide these low-level
features.  However, including these features in the C library may be a
disadvantage if another package provides them as well as there will be
two conflicting versions of them.  Also, the features won’t be available
to projects that do not use the GNU C Library but use other GNU tools,
like GCC.

   The current guidelines are:
   • If the header file provides features that only make sense on a
     particular machine architecture and have nothing to do with an
     operating system, then the features should ultimately be provided
     as GCC built-in functions.  Until then, the GNU C Library may
     provide them in the header file.  When the GCC built-in functions
     become available, those provided in the header file should be made
     conditionally available prior to the GCC version in which the
     built-in function was made available.

   • If the header file provides features that are specific to an
     operating system, both GCC and the GNU C Library could provide it,
     but the GNU C Library is preferred as it already has a lot of
     information about the operating system.

   • If the header file provides features that are specific to an
     operating system but used by the GNU C Library, then the GNU C
     Library should provide them.

   The general solution for providing low-level features is to export
them as follows:

   • A nonstandard, low-level header file that defines macros and inline
     functions should be called ‘sys/platform/NAME.h’.

   • Each header file’s name should include the platform name, to avoid
     users thinking there is anything in common between the different
     header files for different platforms.  For example, a
     ‘sys/platform/ARCH.h’ name such as ‘sys/platform/ppc.h’ is better
     than ‘sys/platform.h’.

   • A platform-specific header file provided by the GNU C Library
     should coordinate with GCC such that compiler built-in versions of
     the functions and macros are preferred if available.  This means
     that user programs will only ever need to include
     ‘sys/platform/ARCH.h’, keeping the same names of types, macros, and
     functions for convenience and portability.

   • Each included symbol must have the prefix ‘__ARCH_’, such as
     ‘__ppc_get_timebase’.

   The easiest way to provide a header file is to add it to the
‘sysdep_headers’ variable.  For example, the combination of
Linux-specific header files on PowerPC could be provided like this:

     sysdep_headers += sys/platform/ppc.h

   Then ensure that you have added a ‘sys/platform/ppc.h’ header file in
the machine-specific directory, e.g.,
‘sysdeps/powerpc/sys/platform/ppc.h’.


File: libc.info,  Node: Porting,  Prev: Source Layout,  Up: Maintenance

D.2 Porting the GNU C Library
=============================

The GNU C Library is written to be easily portable to a variety of
machines and operating systems.  Machine- and operating system-dependent
functions are well separated to make it easy to add implementations for
new machines or operating systems.  This section describes the layout of
the library source tree and explains the mechanisms used to select
machine-dependent code to use.

   All the machine-dependent and operating system-dependent files in the
library are in the subdirectory ‘sysdeps’ under the top-level library
source directory.  This directory contains a hierarchy of subdirectories
(*note Hierarchy Conventions::).

   Each subdirectory of ‘sysdeps’ contains source files for a particular
machine or operating system, or for a class of machine or operating
system (for example, systems by a particular vendor, or all machines
that use IEEE 754 floating-point format).  A configuration specifies an
ordered list of these subdirectories.  Each subdirectory implicitly
appends its parent directory to the list.  For example, specifying the
list ‘unix/bsd/vax’ is equivalent to specifying the list ‘unix/bsd/vax
unix/bsd unix’.  A subdirectory can also specify that it implies other
subdirectories which are not directly above it in the directory
hierarchy.  If the file ‘Implies’ exists in a subdirectory, it lists
other subdirectories of ‘sysdeps’ which are appended to the list,
appearing after the subdirectory containing the ‘Implies’ file.  Lines
in an ‘Implies’ file that begin with a ‘#’ character are ignored as
comments.  For example, ‘unix/bsd/Implies’ contains:
     # BSD has Internet-related things.
     unix/inet
and ‘unix/Implies’ contains:
     posix

So the final list is ‘unix/bsd/vax unix/bsd unix/inet unix posix’.

   ‘sysdeps’ has a “special” subdirectory called ‘generic’.  It is
always implicitly appended to the list of subdirectories, so you needn’t
put it in an ‘Implies’ file, and you should not create any
subdirectories under it intended to be new specific categories.
‘generic’ serves two purposes.  First, the makefiles do not bother to
look for a system-dependent version of a file that’s not in ‘generic’.
This means that any system-dependent source file must have an analogue
in ‘generic’, even if the routines defined by that file are not
implemented on other platforms.  Second, the ‘generic’ version of a
system-dependent file is used if the makefiles do not find a version
specific to the system you’re compiling for.

   If it is possible to implement the routines in a ‘generic’ file in
machine-independent C, using only other machine-independent functions in
the C library, then you should do so.  Otherwise, make them stubs.  A
"stub" function is a function which cannot be implemented on a
particular machine or operating system.  Stub functions always return an
error, and set ‘errno’ to ‘ENOSYS’ (Function not implemented).  *Note
Error Reporting::.  If you define a stub function, you must place the
statement ‘stub_warning(FUNCTION)’, where FUNCTION is the name of your
function, after its definition.  This causes the function to be listed
in the installed ‘<gnu/stubs.h>’, and makes GNU ld warn when the
function is used.

   Some rare functions are only useful on specific systems and aren’t
defined at all on others; these do not appear anywhere in the
system-independent source code or makefiles (including the ‘generic’
directory), only in the system-dependent ‘Makefile’ in the specific
system’s subdirectory.

   If you come across a file that is in one of the main source
directories (‘string’, ‘stdio’, etc.), and you want to write a machine-
or operating system-dependent version of it, move the file into
‘sysdeps/generic’ and write your new implementation in the appropriate
system-specific subdirectory.  Note that if a file is to be
system-dependent, it *must not* appear in one of the main source
directories.

   There are a few special files that may exist in each subdirectory of
‘sysdeps’:

‘Makefile’

     A makefile for this machine or operating system, or class of
     machine or operating system.  This file is included by the library
     makefile ‘Makerules’, which is used by the top-level makefile and
     the subdirectory makefiles.  It can change the variables set in the
     including makefile or add new rules.  It can use GNU ‘make’
     conditional directives based on the variable ‘subdir’ (see above)
     to select different sets of variables and rules for different
     sections of the library.  It can also set the ‘make’ variable
     ‘sysdep-routines’, to specify extra modules to be included in the
     library.  You should use ‘sysdep-routines’ rather than adding
     modules to ‘routines’ because the latter is used in determining
     what to distribute for each subdirectory of the main source tree.

     Each makefile in a subdirectory in the ordered list of
     subdirectories to be searched is included in order.  Since several
     system-dependent makefiles may be included, each should append to
     ‘sysdep-routines’ rather than simply setting it:

          sysdep-routines := $(sysdep-routines) foo bar

‘Subdirs’

     This file contains the names of new whole subdirectories under the
     top-level library source tree that should be included for this
     system.  These subdirectories are treated just like the
     system-independent subdirectories in the library source tree, such
     as ‘stdio’ and ‘math’.

     Use this when there are completely new sets of functions and header
     files that should go into the library for the system this
     subdirectory of ‘sysdeps’ implements.  For example,
     ‘sysdeps/unix/inet/Subdirs’ contains ‘inet’; the ‘inet’ directory
     contains various network-oriented operations which only make sense
     to put in the library on systems that support the Internet.

‘configure’

     This file is a shell script fragment to be run at configuration
     time.  The top-level ‘configure’ script uses the shell ‘.’ command
     to read the ‘configure’ file in each system-dependent directory
     chosen, in order.  The ‘configure’ files are often generated from
     ‘configure.ac’ files using Autoconf.

     A system-dependent ‘configure’ script will usually add things to
     the shell variables ‘DEFS’ and ‘config_vars’; see the top-level
     ‘configure’ script for details.  The script can check for ‘--with-PACKAGE’
     options that were passed to the top-level ‘configure’.  For an
     option ‘--with-PACKAGE=VALUE’ ‘configure’ sets the shell variable ‘with_PACKAGE’
     (with any dashes in PACKAGE converted to underscores) to VALUE; if
     the option is just ‘--with-PACKAGE’ (no argument), then it sets ‘with_PACKAGE’
     to ‘yes’.

‘configure.ac’

     This file is an Autoconf input fragment to be processed into the
     file ‘configure’ in this subdirectory.  *Note
     (autoconf.info)Introduction::, for a description of Autoconf.  You
     should write either ‘configure’ or ‘configure.ac’, but not both.
     The first line of ‘configure.ac’ should invoke the ‘m4’ macro
     ‘GLIBC_PROVIDES’.  This macro does several ‘AC_PROVIDE’ calls for
     Autoconf macros which are used by the top-level ‘configure’ script;
     without this, those macros might be invoked again unnecessarily by
     Autoconf.

   That is the general system for how system-dependencies are isolated.

* Menu:

* Hierarchy Conventions::       The layout of the ‘sysdeps’ hierarchy.
* Porting to Unix::             Porting the library to an average
                                   Unix-like system.


File: libc.info,  Node: Hierarchy Conventions,  Next: Porting to Unix,  Up: Porting

D.2.1 Layout of the ‘sysdeps’ Directory Hierarchy
-------------------------------------------------

A GNU configuration name has three parts: the CPU type, the
manufacturer’s name, and the operating system.  ‘configure’ uses these
to pick the list of system-dependent directories to look for.  If the
‘--nfp’ option is _not_ passed to ‘configure’, the directory
‘MACHINE/fpu’ is also used.  The operating system often has a "base
operating system"; for example, if the operating system is ‘Linux’, the
base operating system is ‘unix/sysv’.  The algorithm used to pick the
list of directories is simple: ‘configure’ makes a list of the base
operating system, manufacturer, CPU type, and operating system, in that
order.  It then concatenates all these together with slashes in between,
to produce a directory name; for example, the configuration ‘i686-linux-gnu’
results in ‘unix/sysv/linux/i386/i686’.  ‘configure’ then tries removing
each element of the list in turn, so ‘unix/sysv/linux’ and ‘unix/sysv’
are also tried, among others.  Since the precise version number of the
operating system is often not important, and it would be very
inconvenient, for example, to have identical ‘irix6.2’ and ‘irix6.3’
directories, ‘configure’ tries successively less specific operating
system names by removing trailing suffixes starting with a period.

   As an example, here is the complete list of directories that would be
tried for the configuration ‘i686-linux-gnu’ (with the ‘crypt’ and
‘linuxthreads’ add-on):

     sysdeps/i386/elf
     crypt/sysdeps/unix
     linuxthreads/sysdeps/unix/sysv/linux
     linuxthreads/sysdeps/pthread
     linuxthreads/sysdeps/unix/sysv
     linuxthreads/sysdeps/unix
     linuxthreads/sysdeps/i386/i686
     linuxthreads/sysdeps/i386
     linuxthreads/sysdeps/pthread/no-cmpxchg
     sysdeps/unix/sysv/linux/i386
     sysdeps/unix/sysv/linux
     sysdeps/gnu
     sysdeps/unix/common
     sysdeps/unix/mman
     sysdeps/unix/inet
     sysdeps/unix/sysv/i386/i686
     sysdeps/unix/sysv/i386
     sysdeps/unix/sysv
     sysdeps/unix/i386
     sysdeps/unix
     sysdeps/posix
     sysdeps/i386/i686
     sysdeps/i386/i486
     sysdeps/libm-i387/i686
     sysdeps/i386/fpu
     sysdeps/libm-i387
     sysdeps/i386
     sysdeps/wordsize-32
     sysdeps/ieee754
     sysdeps/libm-ieee754
     sysdeps/generic

   Different machine architectures are conventionally subdirectories at
the top level of the ‘sysdeps’ directory tree.  For example, ‘sysdeps/sparc’
and ‘sysdeps/m68k’.  These contain files specific to those machine
architectures, but not specific to any particular operating system.
There might be subdirectories for specializations of those
architectures, such as ‘sysdeps/m68k/68020’.  Code which is specific to
the floating-point coprocessor used with a particular machine should go
in ‘sysdeps/MACHINE/fpu’.

   There are a few directories at the top level of the ‘sysdeps’
hierarchy that are not for particular machine architectures.

‘generic’
     As described above (*note Porting::), this is the subdirectory that
     every configuration implicitly uses after all others.

‘ieee754’
     This directory is for code using the IEEE 754 floating-point
     format, where the C type ‘float’ is IEEE 754 single-precision
     format, and ‘double’ is IEEE 754 double-precision format.  Usually
     this directory is referred to in the ‘Implies’ file in a machine
     architecture-specific directory, such as ‘m68k/Implies’.

‘libm-ieee754’
     This directory contains an implementation of a mathematical library
     usable on platforms which use IEEE 754 conformant floating-point
     arithmetic.

‘libm-i387’
     This is a special case.  Ideally the code should be in
     ‘sysdeps/i386/fpu’ but for various reasons it is kept aside.

‘posix’
     This directory contains implementations of things in the library in
     terms of POSIX.1 functions.  This includes some of the POSIX.1
     functions themselves.  Of course, POSIX.1 cannot be completely
     implemented in terms of itself, so a configuration using just
     ‘posix’ cannot be complete.

‘unix’
     This is the directory for Unix-like things.  *Note Porting to
     Unix::.  ‘unix’ implies ‘posix’.  There are some special-purpose
     subdirectories of ‘unix’:

     ‘unix/common’
          This directory is for things common to both BSD and System V
          release 4.  Both ‘unix/bsd’ and ‘unix/sysv/sysv4’ imply
          ‘unix/common’.

     ‘unix/inet’
          This directory is for ‘socket’ and related functions on Unix
          systems.  ‘unix/inet/Subdirs’ enables the ‘inet’ top-level
          subdirectory.  ‘unix/common’ implies ‘unix/inet’.

‘mach’
     This is the directory for things based on the Mach microkernel from
     CMU (including GNU/Hurd systems).  Other basic operating systems
     (VMS, for example) would have their own directories at the top
     level of the ‘sysdeps’ hierarchy, parallel to ‘unix’ and ‘mach’.


File: libc.info,  Node: Porting to Unix,  Prev: Hierarchy Conventions,  Up: Porting

D.2.2 Porting the GNU C Library to Unix Systems
-----------------------------------------------

Most Unix systems are fundamentally very similar.  There are variations
between different machines, and variations in what facilities are
provided by the kernel.  But the interface to the operating system
facilities is, for the most part, pretty uniform and simple.

   The code for Unix systems is in the directory ‘unix’, at the top
level of the ‘sysdeps’ hierarchy.  This directory contains
subdirectories (and subdirectory trees) for various Unix variants.

   The functions which are system calls in most Unix systems are
implemented in assembly code, which is generated automatically from
specifications in files named ‘syscalls.list’.  There are several such
files, one in ‘sysdeps/unix’ and others in its subdirectories.  Some
special system calls are implemented in files that are named with a
suffix of ‘.S’; for example, ‘_exit.S’.  Files ending in ‘.S’ are run
through the C preprocessor before being fed to the assembler.

   These files all use a set of macros that should be defined in
‘sysdep.h’.  The ‘sysdep.h’ file in ‘sysdeps/unix’ partially defines
them; a ‘sysdep.h’ file in another directory must finish defining them
for the particular machine and operating system variant.  See
‘sysdeps/unix/sysdep.h’ and the machine-specific ‘sysdep.h’
implementations to see what these macros are and what they should do.

   The system-specific makefile for the ‘unix’ directory
(‘sysdeps/unix/Makefile’) gives rules to generate several files from the
Unix system you are building the library on (which is assumed to be the
target system you are building the library _for_).  All the generated
files are put in the directory where the object files are kept; they
should not affect the source tree itself.  The files generated are
‘ioctls.h’, ‘errnos.h’, ‘sys/param.h’, and ‘errlist.c’ (for the ‘stdio’
section of the library).


File: libc.info,  Node: Platform,  Next: Contributors,  Prev: Maintenance,  Up: Top

Appendix E Platform-specific facilities
***************************************

The GNU C Library can provide machine-specific functionality.

* Menu:

* PowerPC::           Facilities Specific to the PowerPC Architecture


File: libc.info,  Node: PowerPC,  Up: Platform

E.1 PowerPC-specific Facilities
===============================

Facilities specific to PowerPC that are not specific to a particular
operating system are declared in ‘sys/platform/ppc.h’.

 -- Function: uint64_t __ppc_get_timebase (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Read the current value of the Time Base Register.

     The "Time Base Register" is a 64-bit register that stores a
     monotonically incremented value updated at a system-dependent
     frequency that may be different from the processor frequency.  More
     information is available in ‘Power ISA 2.06b - Book II - Section
     5.2’.

     ‘__ppc_get_timebase’ uses the processor’s time base facility
     directly without requiring assistance from the operating system, so
     it is very efficient.

 -- Function: uint64_t __ppc_get_timebase_freq (void)
     Preliminary: | MT-Unsafe init | AS-Unsafe corrupt:init | AC-Unsafe
     corrupt:init | *Note POSIX Safety Concepts::.

     Read the current frequency at which the Time Base Register is
     updated.

     This frequency is not related to the processor clock or the bus
     clock.  It is also possible that this frequency is not constant.
     More information is available in ‘Power ISA 2.06b - Book II -
     Section 5.2’.

   The following functions provide hints about the usage of resources
that are shared with other processors.  They can be used, for example,
if a program waiting on a lock intends to divert the shared resources to
be used by other processors.  More information is available in ‘Power
ISA 2.06b - Book II - Section 3.2’.

 -- Function: void __ppc_yield (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Provide a hint that performance will probably be improved if shared
     resources dedicated to the executing processor are released for use
     by other processors.

 -- Function: void __ppc_mdoio (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Provide a hint that performance will probably be improved if shared
     resources dedicated to the executing processor are released until
     all outstanding storage accesses to caching-inhibited storage have
     been completed.

 -- Function: void __ppc_mdoom (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Provide a hint that performance will probably be improved if shared
     resources dedicated to the executing processor are released until
     all outstanding storage accesses to cacheable storage for which the
     data is not in the cache have been completed.

 -- Function: void __ppc_set_ppr_med (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Set the Program Priority Register to medium value (default).

     The "Program Priority Register" (PPR) is a 64-bit register that
     controls the program’s priority.  By adjusting the PPR value the
     programmer may improve system throughput by causing the system
     resources to be used more efficiently, especially in contention
     situations.  The three unprivileged states available are covered by
     the functions ‘__ppc_set_ppr_med’ (medium – default),
     ‘__ppc_set_ppc_low’ (low) and ‘__ppc_set_ppc_med_low’ (medium low).
     More information available in ‘Power ISA 2.06b - Book II - Section
     3.1’.

 -- Function: void __ppc_set_ppr_low (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Set the Program Priority Register to low value.

 -- Function: void __ppc_set_ppr_med_low (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Set the Program Priority Register to medium low value.

   Power ISA 2.07 extends the priorities that can be set to the Program
Priority Register (PPR). The following functions implement the new
priority levels: very low and medium high.

 -- Function: void __ppc_set_ppr_very_low (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Set the Program Priority Register to very low value.

 -- Function: void __ppc_set_ppr_med_high (void)
     Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
     Concepts::.

     Set the Program Priority Register to medium high value.  The medium
     high priority is privileged and may only be set during certain time
     intervals by problem-state programs.  If the program priority is
     medium high when the time interval expires or if an attempt is made
     to set the priority to medium high when it is not allowed, the
     priority is set to medium.


File: libc.info,  Node: Contributors,  Next: Free Manuals,  Prev: Platform,  Up: Top

Appendix F Contributors to the GNU C Library
********************************************

The GNU C Library project would like to thank its many contributors.
Without them the project would not have been nearly as successful as it
has been.  Any omissions in this list are accidental.  Feel free to file
a bug in bugzilla if you have been left out or some of your
contributions are not listed.  Please keep this list in alphabetical
order.

   • Nick Alcock for contributing fixes to allow the GNU C Library to be
     built with the stack smashing protector enabled.

   • Ryan S. Arnold for his improvements for Linux on PowerPC and his
     direction as FSF Project Steward for the GNU C Library.

   • Miles Bader for writing the ‘argp’ argument-parsing package, and
     the ‘argz’/‘envz’ interfaces.

   • Jeff Bailey for his maintainership of the HPPA architecture.

   • Petr Baudis for bug fixes and testing.

   • Stephen R. van den Berg for contributing a highly-optimized
     ‘strstr’ function.

   • Ondrej Bilka for contributing optimized string routines for x64 and
     various fixes.

   • Eric Blake for adding O(n) implementations of ‘memmem’, ‘strstr’
     and ‘strcasestr’.

   • Philip Blundell for the ports to Linux/ARM
     (‘arm-ANYTHING-linuxaout’) and ARM standalone
     (‘arm-ANYTHING-none’), as well as for parts of the IPv6 support
     code.

   • Per Bothner for the implementation of the ‘libio’ library which is
     used to implement ‘stdio’ functions.

   • Mark Brown for his direction as part of the GNU C Library steering
     committee.

   • Thomas Bushnell for his contributions to Hurd.

   • Wilco Dijkstra for various fixes.

   • Liubov Dmitrieva for optimized string and math functions on x86-64
     and x86.

   • Ulrich Drepper for his many contributions in almost all parts of
     the GNU C Library, including:
        • internationalization support, including the ‘locale’ and
          ‘localedef’ utilities.
        • Linux i386/ELF support
        • the ‘hsearch’ and ‘drand48’ families of functions, reentrant
          ‘…‘_r’’ versions of the ‘random’ family; System V shared
          memory and IPC support code
        • several highly-optimized string functions for iX86 processors
        • many math functions
        • the character conversion functions (‘iconv’)
        • the ‘ftw’ and ‘nftw’ functions
        • the floating-point printing function used by ‘printf’ and
          friends and the floating-point reading function used by
          ‘scanf’, ‘strtod’ and friends
        • the ‘catgets’ support and the entire suite of multi-byte and
          wide-character support functions (‘wctype.h’, ‘wchar.h’,
          etc.).
        • versioning of objects on the symbol level

   • Wilco Dijkstra for various fixes.

   • Richard Earnshaw for continued support and fixes to the various ARM
     machine files.

   • Paul Eggert for the ‘mktime’ function and for his direction as part
     of the GNU C Library steering committee.

   • Steve Ellcey for various fixes.

   • Tulio Magno Quites Machado Filho for adding a new class of
     installed headers for low-level platform-specific functionality and
     one such for PowerPC and various fixes.

   • Mike Frysinger for his maintaining of the IA64 architecture and for
     testing and bug fixing.

   • Martin Galvan for contributing gdb pretty printer support to glibc
     and adding an initial set of pretty printers for structures in the
     POSIX Threads library.

   • Michael Glad for the DES encryption function ‘crypt’ and related
     functions.

   • Wolfram Gloger for contributing the memory allocation functions
     functions ‘malloc’, ‘realloc’ and ‘free’ and related code.

   • Torbjörn Granlund for fast implementations of many of the string
     functions (‘memcpy’, ‘strlen’, etc.).

   • Michael J. Haertel for writing the merge sort function ‘qsort’ and
     malloc checking functions like ‘mcheck’.

   • Bruno Haible for his improvements to the ‘iconv’ and locale
     implementations.

   • Richard Henderson for the port to Linux on Alpha
     (‘alpha-ANYTHING-linux’).

   • David Holsgrove for the port to Linux on MicroBlaze.

   • Daniel Jacobowitz for various fixes and enhancements.

   • Andreas Jaeger for the port to Linux on x86-64
     (‘x86_64-ANYTHING-linux’ and his work on Linux for MIPS
     (‘mips-ANYTHING-linux’), implementing the ‘ldconfig’ program,
     providing a test suite for the math library and for his direction
     as part of the GNU C Library steering committee.

   • Aurelien Jarno for various fixes.

   • Rical Jasan for contributing various fixes in the GNU C Library
     manual.

   • Jakub Jelinek for implementing a number of checking functions and
     for his direction as part of the GNU C Library steering committee.

   • Geoffrey Keating for the port to Linux on PowerPC
     (‘powerpc-ANYTHING-linux’).

   • Brendan Kehoe for contributing the port to the MIPS DECStation
     running Ultrix 4 (‘mips-dec-ultrix4’) and the port to the DEC Alpha
     running OSF/1 (‘alpha-dec-osf1’).

   • Mark Kettenis for implementing the ‘utmpx’ interface and a utmp
     daemon, and for a Hesiod NSS module.

   • Andi Kleen for implementing pthreads lock elision with TSX.

   • Kazumoto Kojima for the port of the Mach and Hurd code to the MIPS
     architecture (‘mips-ANYTHING-gnu’) and for his work on the SH
     architecture.

   • Maxim Kuvyrkov for various fixes.

   • Andreas Krebbel for his work on Linux for s390 and s390x.

   • Thorsten Kukuk for providing an implementation for NIS (YP) and
     NIS+, securelevel 0, 1 and 2 and for the implementation for a
     caching daemon for NSS (‘nscd’).

   • Jeff Law for various fixes.

   • Doug Lea for contributing the memory allocation functions ‘malloc’,
     ‘realloc’ and ‘free’ and related code.

   • Chris Leonard for various fixes and enhancements to localedata.

   • Stefan Liebler for various fixes.

   • Hongjiu Lu for providing the support for a Linux 32-bit runtime
     environment under x86-64 (x32), for porting to Linux on IA64, for
     improved string functions, a framework for testing IFUNC
     implementations, and many bug fixes.

   • Luis Machado for optimized functions on PowerPC.

   • David J. MacKenzie for his contribution to the ‘getopt’ function
     and writing the ‘tar.h’ header.

   • Greg McGary for adding runtime support for bounds checking.

   • Roland McGrath for writing most of the GNU C Library originally,
     for his work on the Hurd port, his direction as part of the GNU C
     Library steering committee and as FSF Project Steward for the GNU C
     Library, and for many bug fixes and reviewing of contributions.

   • Allan McRae for various fixes.

   • Jason Merrill for the port to the Sequent Symmetry running Dynix
     version 3 (‘i386-sequent-bsd’).

   • Chris Metcalf for the port to Linux/Tile (‘tilegx-ANYTHING-linux’
     and ‘tilepro-ANYTHING-linux’).

   • David Miller for contributing the port to Linux/Sparc
     (‘sparc*-ANYTHING-linux’).

   • Alan Modra for his improvements for Linux on PowerPC.

   • David Mosberger-Tang for contributing the port to Linux/Alpha
     (‘alpha-ANYTHING-linux’).

   • Stephen Moshier for implementing some 128-bit long double format
     math functions.

   • Stephen Munroe for his port to Linux on PowerPC64
     (‘powerpc64-ANYTHING-linux’) and for adding optimized
     implementations for PowerPC.

   • Paul E. Murphy for various fixes on PowerPC.

   • Joseph S. Myers for numerous bug fixes for the libm functions, for
     his maintainership of the ARM and MIPS architectures, improving
     cross-compilation and cross-testing of the GNU C Library, expanded
     coverage of conformtest, merging the ports/ subdirectory into the
     GNU C Library main repository and his direction as FSF Project
     Steward for the GNU C Library.

   • Szabolcs Nagy for various fixes.

   • Will Newton for contributing some optimized string functions and
     pointer encryption support for ARM and various fixes.

   • Carlos O’Donell for his maintainership of the HPPA architecture,
     for maintaining the GNU C Library web pages and wiki, for his
     direction as FSF Project Steward for the GNU C Library and various
     bug fixes.

   • Alexandre Oliva for adding TLS descriptors for LD and GD on x86 and
     x86-64, for the am33 port, for completing the MIPS n64/n32/o32
     multilib port, for thread-safety, async-signal safety and
     async-cancellation safety documentation in the manual, for his
     direction as FSF Project Maintainer and for various fixes.

   • Paul Pluzhnikov for various fixes.

   • Marek Polacek for various fixes.

   • Siddhesh Poyarekar for various fixes, an implementation of a
     framework for performance benchmarking of functions and
     implementating the tunables infrastructure.

   • Tom Quinn for contributing the startup code to support SunOS shared
     libraries and the port to SGI machines running Irix 4
     (‘mips-sgi-irix4’).

   • Torvald Riegel for the implementation of new algorithms for
     semaphores, pthread_rwlock and condition variables.

   • Maciej W. Rozycki for various fixes.

   • Pravin Satpute for writing sorting rules for some Indian languages.

   • Douglas C. Schmidt for writing the quick sort function used as a
     fallback by ‘qsort’.

   • Will Schmidt for optimized string functions on PowerPC.

   • Andreas Schwab for the port to Linux/m68k (‘m68k-ANYTHING-linux’)
     and for his direction as part of the GNU C Library steering
     committee.

   • Martin Schwidefsky for porting to Linux on s390
     (‘s390-ANYTHING-linux’) and s390x (‘s390x-ANYTHING-linux’).

   • Thomas Schwinge for his contribution to Hurd and the SH
     architecture.

   • Andrew Senkevich for contributing vector math function
     implementations for x86.

   • Carlos Eduardo Seo for optimized functions on PowerPC.

   • Marcus Shawcroft for contributing the AArch64 port.

   • Franz Sirl for various fixes.

   • Jes Sorensen for porting to Linux on IA64 (‘ia64-ANYTHING-linux’).

   • Rajalakshmi Srinivasaraghavan for various fixes and optimizations
     on PowerPC.

   • Richard Stallman for his contribution to the ‘getopt’ function.

   • Alfred M. Szmidt for various fixes.

   • Ian Lance Taylor for contributing the port to the MIPS DECStation
     running Ultrix 4 (‘mips-dec-ultrix4’).

   • Samuel Thibault for improving the Hurd port.

   • Tim Waugh for the implementation of the POSIX.2 ‘wordexp’ function
     family.

   • Zack Weinberg for the ‘explicit_bzero’ implementation and for
     various fixes.

   • Eric Youngdale for implementing versioning of objects on the symbol
     level.

   • Adhemerval Zanella for optimized functions on PowerPC and various
     fixes.

   Some code in the GNU C Library comes from other projects and might be
under a different license:

   • The timezone support code is derived from the public-domain
     timezone package by Arthur David Olson and his many contributors.

   • Some of the support code for Mach is taken from Mach 3.0 by CMU;
     the file ‘if_ppp.h’ is also copyright by CMU, but under a different
     license; see the file ‘LICENSES’ for the text of the licenses.

   • The random number generation functions ‘random’, ‘srandom’,
     ‘setstate’ and ‘initstate’, which are also the basis for the ‘rand’
     and ‘srand’ functions, were written by Earl T. Cohen for the
     University of California at Berkeley and are copyrighted by the
     Regents of the University of California.  They have undergone minor
     changes to fit into the GNU C Library and to fit the ISO C
     standard, but the functional code is Berkeley’s.

   • The Internet-related code (most of the ‘inet’ subdirectory) and
     several other miscellaneous functions and header files have been
     included from 4.4 BSD with little or no modification.  The copying
     permission notice for this code can be found in the file ‘LICENSES’
     in the source distribution.

   • The ‘getaddrinfo’ and ‘getnameinfo’ functions and supporting code
     were written by Craig Metz; see the file ‘LICENSES’ for details on
     their licensing.

   • The DNS resolver code is taken directly from BIND 4.9.5, which
     includes copyrighted code from UC Berkeley and from Digital
     Equipment Corporation.  See the file ‘LICENSES’ for the text of the
     DEC license.

   • The code to support Sun RPC is taken verbatim from Sun’s RPCSRC-4.0
     distribution; see the file ‘LICENSES’ for the text of the license.

   • The math functions are taken from ‘fdlibm-5.1’ by Sun Microsystems,
     as modified by J.T. Conklin, Ian Lance Taylor, Ulrich Drepper,
     Andreas Schwab, and Roland McGrath.

   • Many of the IEEE 64-bit double precision math functions (in the
     ‘sysdeps/ieee754/dbl-64’ subdirectory) come from the IBM Accurate
     Mathematical Library, contributed by IBM.

   • Many of the IA64 math functions are taken from a collection of
     “Highly Optimized Mathematical Functions for Itanium” that Intel
     makes available under a free license; see the file ‘LICENSES’ for
     details.


File: libc.info,  Node: Free Manuals,  Next: Copying,  Prev: Contributors,  Up: Top

Appendix G Free Software Needs Free Documentation
*************************************************

The biggest deficiency in the free software community today is not in
the software—it is the lack of good free documentation that we can
include with the free software.  Many of our most important programs do
not come with free reference manuals and free introductory texts.
Documentation is an essential part of any software package; when an
important free software package does not come with a free manual and a
free tutorial, that is a major gap.  We have many such gaps today.

   Consider Perl, for instance.  The tutorial manuals that people
normally use are non-free.  How did this come about?  Because the
authors of those manuals published them with restrictive terms—no
copying, no modification, source files not available—which exclude them
from the free software world.

   That wasn’t the first time this sort of thing happened, and it was
far from the last.  Many times we have heard a GNU user eagerly describe
a manual that he is writing, his intended contribution to the community,
only to learn that he had ruined everything by signing a publication
contract to make it non-free.

   Free documentation, like free software, is a matter of freedom, not
price.  The problem with the non-free manual is not that publishers
charge a price for printed copies—that in itself is fine.  (The Free
Software Foundation sells printed copies of manuals, too.)  The problem
is the restrictions on the use of the manual.  Free manuals are
available in source code form, and give you permission to copy and
modify.  Non-free manuals do not allow this.

   The criteria of freedom for a free manual are roughly the same as for
free software.  Redistribution (including the normal kinds of commercial
redistribution) must be permitted, so that the manual can accompany
every copy of the program, both on-line and on paper.

   Permission for modification of the technical content is crucial too.
When people modify the software, adding or changing features, if they
are conscientious they will change the manual too—so they can provide
accurate and clear documentation for the modified program.  A manual
that leaves you no choice but to write a new manual to document a
changed version of the program is not really available to our community.

   Some kinds of limits on the way modification is handled are
acceptable.  For example, requirements to preserve the original author’s
copyright notice, the distribution terms, or the list of authors, are
ok.  It is also no problem to require modified versions to include
notice that they were modified.  Even entire sections that may not be
deleted or changed are acceptable, as long as they deal with
nontechnical topics (like this one).  These kinds of restrictions are
acceptable because they don’t obstruct the community’s normal use of the
manual.

   However, it must be possible to modify all the _technical_ content of
the manual, and then distribute the result in all the usual media,
through all the usual channels.  Otherwise, the restrictions obstruct
the use of the manual, it is not free, and we need another manual to
replace it.

   Please spread the word about this issue.  Our community continues to
lose manuals to proprietary publishing.  If we spread the word that free
software needs free reference manuals and free tutorials, perhaps the
next person who wants to contribute by writing documentation will
realize, before it is too late, that only free manuals contribute to the
free software community.

   If you are writing documentation, please insist on publishing it
under the GNU Free Documentation License or another free documentation
license.  Remember that this decision requires your approval—you don’t
have to let the publisher decide.  Some commercial publishers will use a
free license if you insist, but they will not propose the option; it is
up to you to raise the issue and say firmly that this is what you want.
If the publisher you are dealing with refuses, please try other
publishers.  If you’re not sure whether a proposed license is free,
write to <licensing@gnu.org>.

   You can encourage commercial publishers to sell more free, copylefted
manuals and tutorials by buying them, and particularly by buying copies
from the publishers that paid for their writing or for major
improvements.  Meanwhile, try to avoid buying non-free documentation at
all.  Check the distribution terms of a manual before you buy it, and
insist that whoever seeks your business must respect your freedom.
Check the history of the book, and try reward the publishers that have
paid or pay the authors to work on it.

   The Free Software Foundation maintains a list of free documentation
published by other publishers, at
<http://www.fsf.org/doc/other-free-books.html>.


File: libc.info,  Node: Copying,  Next: Documentation License,  Prev: Free Manuals,  Up: Top

Appendix H GNU Lesser General Public License
********************************************

                      Version 2.1, February 1999

     Copyright © 1991, 1999 Free Software Foundation, Inc.
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA

     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.

     [This is the first released version of the Lesser GPL.  It also counts
     as the successor of the GNU Library Public License, version 2, hence the
     version number 2.1.]

Preamble
--------

The licenses for most software are designed to take away your freedom to
share and change it.  By contrast, the GNU General Public Licenses are
intended to guarantee your freedom to share and change free software—to
make sure the software is free for all its users.

   This license, the Lesser General Public License, applies to some
specially designated software—typically libraries—of the Free Software
Foundation and other authors who decide to use it.  You can use it too,
but we suggest you first think carefully about whether this license or
the ordinary General Public License is the better strategy to use in any
particular case, based on the explanations below.

   When we speak of free software, we are referring to freedom of use,
not price.  Our General Public Licenses are designed to make sure that
you have the freedom to distribute copies of free software (and charge
for this service if you wish); that you receive source code or can get
it if you want it; that you can change the software and use pieces of it
in new free programs; and that you are informed that you can do these
things.

   To protect your rights, we need to make restrictions that forbid
distributors to deny you these rights or to ask you to surrender these
rights.  These restrictions translate to certain responsibilities for
you if you distribute copies of the library or if you modify it.

   For example, if you distribute copies of the library, whether gratis
or for a fee, you must give the recipients all the rights that we gave
you.  You must make sure that they, too, receive or can get the source
code.  If you link other code with the library, you must provide
complete object files to the recipients, so that they can relink them
with the library after making changes to the library and recompiling it.
And you must show them these terms so they know their rights.

   We protect your rights with a two-step method: (1) we copyright the
library, and (2) we offer you this license, which gives you legal
permission to copy, distribute and/or modify the library.

   To protect each distributor, we want to make it very clear that there
is no warranty for the free library.  Also, if the library is modified
by someone else and passed on, the recipients should know that what they
have is not the original version, so that the original author’s
reputation will not be affected by problems that might be introduced by
others.

   Finally, software patents pose a constant threat to the existence of
any free program.  We wish to make sure that a company cannot
effectively restrict the users of a free program by obtaining a
restrictive license from a patent holder.  Therefore, we insist that any
patent license obtained for a version of the library must be consistent
with the full freedom of use specified in this license.

   Most GNU software, including some libraries, is covered by the
ordinary GNU General Public License.  This license, the GNU Lesser
General Public License, applies to certain designated libraries, and is
quite different from the ordinary General Public License.  We use this
license for certain libraries in order to permit linking those libraries
into non-free programs.

   When a program is linked with a library, whether statically or using
a shared library, the combination of the two is legally speaking a
combined work, a derivative of the original library.  The ordinary
General Public License therefore permits such linking only if the entire
combination fits its criteria of freedom.  The Lesser General Public
License permits more lax criteria for linking other code with the
library.

   We call this license the "Lesser" General Public License because it
does _Less_ to protect the user’s freedom than the ordinary General
Public License.  It also provides other free software developers Less of
an advantage over competing non-free programs.  These disadvantages are
the reason we use the ordinary General Public License for many
libraries.  However, the Lesser license provides advantages in certain
special circumstances.

   For example, on rare occasions, there may be a special need to
encourage the widest possible use of a certain library, so that it
becomes a de-facto standard.  To achieve this, non-free programs must be
allowed to use the library.  A more frequent case is that a free library
does the same job as widely used non-free libraries.  In this case,
there is little to gain by limiting the free library to free software
only, so we use the Lesser General Public License.

   In other cases, permission to use a particular library in non-free
programs enables a greater number of people to use a large body of free
software.  For example, permission to use the GNU C Library in non-free
programs enables many more people to use the whole GNU operating system,
as well as its variant, the GNU/Linux operating system.

   Although the Lesser General Public License is Less protective of the
users’ freedom, it does ensure that the user of a program that is linked
with the Library has the freedom and the wherewithal to run that program
using a modified version of the Library.

   The precise terms and conditions for copying, distribution and
modification follow.  Pay close attention to the difference between a
“work based on the library” and a “work that uses the library”.  The
former contains code derived from the library, whereas the latter must
be combined with the library in order to run.

TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
---------------------------------------------------------------

  0. This License Agreement applies to any software library or other
     program which contains a notice placed by the copyright holder or
     other authorized party saying it may be distributed under the terms
     of this Lesser General Public License (also called “this License”).
     Each licensee is addressed as “you”.

     A “library” means a collection of software functions and/or data
     prepared so as to be conveniently linked with application programs
     (which use some of those functions and data) to form executables.

     The “Library”, below, refers to any such software library or work
     which has been distributed under these terms.  A “work based on the
     Library” means either the Library or any derivative work under
     copyright law: that is to say, a work containing the Library or a
     portion of it, either verbatim or with modifications and/or
     translated straightforwardly into another language.  (Hereinafter,
     translation is included without limitation in the term
     “modification”.)

     “Source code” for a work means the preferred form of the work for
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END OF TERMS AND CONDITIONS
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How to Apply These Terms to Your New Libraries
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   That’s all there is to it!