Address-Locations.html 5.3 KB

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  65. <h4 class="subsection">9.2.3 Address Locations</h4>
  66. <a name="index-address-locations"></a>
  67. <p><em>Address locations</em> indicate a specific program address. They have
  68. the generalized form *<var>address</var>.
  69. </p>
  70. <p>For line-oriented commands, such as <code>list</code> and <code>edit</code>, this
  71. specifies a source line that contains <var>address</var>. For <code>break</code> and
  72. other breakpoint-oriented commands, this can be used to set breakpoints in
  73. parts of your program which do not have debugging information or
  74. source files.
  75. </p>
  76. <p>Here <var>address</var> may be any expression valid in the current working
  77. language (see <a href="Languages.html#Languages">working language</a>) that specifies a code
  78. address. In addition, as a convenience, <small>GDB</small> extends the
  79. semantics of expressions used in locations to cover several situations
  80. that frequently occur during debugging. Here are the various forms
  81. of <var>address</var>:
  82. </p>
  83. <dl compact="compact">
  84. <dt><code><var>expression</var></code></dt>
  85. <dd><p>Any expression valid in the current working language.
  86. </p>
  87. </dd>
  88. <dt><code><var>funcaddr</var></code></dt>
  89. <dd><p>An address of a function or procedure derived from its name. In C,
  90. C<tt>++</tt>, Objective-C, Fortran, minimal, and assembly, this is
  91. simply the function&rsquo;s name <var>function</var> (and actually a special case
  92. of a valid expression). In Pascal and Modula-2, this is
  93. <code>&amp;<var>function</var></code>. In Ada, this is <code><var>function</var>'Address</code>
  94. (although the Pascal form also works).
  95. </p>
  96. <p>This form specifies the address of the function&rsquo;s first instruction,
  97. before the stack frame and arguments have been set up.
  98. </p>
  99. </dd>
  100. <dt><code>'<var>filename</var>':<var>funcaddr</var></code></dt>
  101. <dd><p>Like <var>funcaddr</var> above, but also specifies the name of the source
  102. file explicitly. This is useful if the name of the function does not
  103. specify the function unambiguously, e.g., if there are several
  104. functions with identical names in different source files.
  105. </p></dd>
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