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<title>The GNU Fortran Compiler: FSEEK</title>

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<a name="FSEEK"></a>
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<hr>
<a name="FSEEK-_002d_002d_002d-Low-level-file-positioning-subroutine"></a>
<h3 class="section">9.115 <code>FSEEK</code> &mdash; Low level file positioning subroutine</h3>
<a name="index-FSEEK"></a>
<a name="index-file-operation_002c-seek"></a>
<a name="index-file-operation_002c-position"></a>

<dl compact="compact">
<dt><em>Description</em>:</dt>
<dd><p>Moves <var>UNIT</var> to the specified <var>OFFSET</var>. If <var>WHENCE</var> 
is set to 0, the <var>OFFSET</var> is taken as an absolute value <code>SEEK_SET</code>,
if set to 1, <var>OFFSET</var> is taken to be relative to the current position 
<code>SEEK_CUR</code>, and if set to 2 relative to the end of the file <code>SEEK_END</code>.
On error, <var>STATUS</var> is set to a nonzero value. If <var>STATUS</var> the seek 
fails silently.
</p>
<p>This intrinsic routine is not fully backwards compatible with <code>g77</code>. 
In <code>g77</code>, the <code>FSEEK</code> takes a statement label instead of a 
<var>STATUS</var> variable. If FSEEK is used in old code, change
</p><div class="smallexample">
<pre class="smallexample">  CALL FSEEK(UNIT, OFFSET, WHENCE, *label)
</pre></div>
<p>to
</p><div class="smallexample">
<pre class="smallexample">  INTEGER :: status
  CALL FSEEK(UNIT, OFFSET, WHENCE, status)
  IF (status /= 0) GOTO label
</pre></div>

<p>Please note that GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code 
for future portability. See also <a href="Fortran-2003-status.html#Fortran-2003-status">Fortran 2003 status</a>.
</p>
</dd>
<dt><em>Standard</em>:</dt>
<dd><p>GNU extension
</p>
</dd>
<dt><em>Class</em>:</dt>
<dd><p>Subroutine
</p>
</dd>
<dt><em>Syntax</em>:</dt>
<dd><p><code>CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])</code>
</p>
</dd>
<dt><em>Arguments</em>:</dt>
<dd><table>
<tr><td width="15%"><var>UNIT</var></td><td width="70%">Shall be a scalar of type <code>INTEGER</code>.</td></tr>
<tr><td width="15%"><var>OFFSET</var></td><td width="70%">Shall be a scalar of type <code>INTEGER</code>.</td></tr>
<tr><td width="15%"><var>WHENCE</var></td><td width="70%">Shall be a scalar of type <code>INTEGER</code>.
Its value shall be either 0, 1 or 2.</td></tr>
<tr><td width="15%"><var>STATUS</var></td><td width="70%">(Optional) shall be a scalar of type 
<code>INTEGER(4)</code>.</td></tr>
</table>

</dd>
<dt><em>Example</em>:</dt>
<dd><div class="smallexample">
<pre class="smallexample">PROGRAM test_fseek
  INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2
  INTEGER :: fd, offset, ierr

  ierr   = 0
  offset = 5
  fd     = 10

  OPEN(UNIT=fd, FILE=&quot;fseek.test&quot;)
  CALL FSEEK(fd, offset, SEEK_SET, ierr)  ! move to OFFSET
  print *, FTELL(fd), ierr

  CALL FSEEK(fd, 0, SEEK_END, ierr)       ! move to end
  print *, FTELL(fd), ierr

  CALL FSEEK(fd, 0, SEEK_SET, ierr)       ! move to beginning
  print *, FTELL(fd), ierr

  CLOSE(UNIT=fd)
END PROGRAM
</pre></div>

</dd>
<dt><em>See also</em>:</dt>
<dd><p><a href="FTELL.html#FTELL">FTELL</a>
</p></dd>
</dl>


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