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<h3 class="section">8.90 <code>FSEEK</code> — Low level file positioning subroutine</h3>
<p><a name="index-FSEEK-631"></a><a name="index-file-operation_002c-seek-632"></a><a name="index-file-operation_002c-position-633"></a>
<dl>
<dt><em>Description</em>:<dd>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>This intrinsic routine is not fully backwards compatible with <samp><span class="command">g77</span></samp>.
In <samp><span class="command">g77</span></samp>, the <code>FSEEK</code> takes a statement label instead of a
<var>STATUS</var> variable. If FSEEK is used in old code, change
<pre class="smallexample"> CALL FSEEK(UNIT, OFFSET, WHENCE, *label)
</pre>
<p>to
<pre class="smallexample"> INTEGER :: status
CALL FSEEK(UNIT, OFFSET, WHENCE, status)
IF (status /= 0) GOTO label
</pre>
<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>.
<br><dt><em>Standard</em>:<dd>GNU extension
<br><dt><em>Class</em>:<dd>Subroutine
<br><dt><em>Syntax</em>:<dd><code>CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])</code>
<br><dt><em>Arguments</em>:<dd>
<p><table summary=""><tr align="left"><td valign="top" width="15%"><var>UNIT</var> </td><td valign="top" width="70%">Shall be a scalar of type <code>INTEGER</code>.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>OFFSET</var> </td><td valign="top" width="70%">Shall be a scalar of type <code>INTEGER</code>.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>WHENCE</var> </td><td valign="top" width="70%">Shall be a scalar of type <code>INTEGER</code>.
Its value shall be either 0, 1 or 2.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>STATUS</var> </td><td valign="top" width="70%">(Optional) shall be a scalar of type
<code>INTEGER(4)</code>.
<br></td></tr></table>
<br><dt><em>Example</em>:<dd>
<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="fseek.test")
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>
<br><dt><em>See also</em>:<dd><a href="FTELL.html#FTELL">FTELL</a>
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