694 lines
18 KiB
HTML
694 lines
18 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
|
|
<title>lseek()--Set File Read/Write Offset</title>
|
|
<!-- Begin Header Records ========================================== -->
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
|
<!-- US Government Users Restricted Rights -->
|
|
<!-- Use, duplication or disclosure restricted by -->
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
|
<!-- Change History: -->
|
|
<!-- YYMMDD USERID Change description -->
|
|
<!-- file cleaned -->
|
|
<!-- Unix2 SCRIPT J converted by B2H R4.1 (346) (CMS) by V2KEA304 -->
|
|
<!-- at RCHVMW2 on 17 Feb 1999 at 11:05:09 -->
|
|
<!-- 010703 JTROUS Chg for PTR SE01918, less restrictive on CCSID, -->
|
|
<!-- also add info on dev/zero, v5r2 -->
|
|
<!-- 011022 JTROUS Changes from API Review 1, V5R2 -->
|
|
<!-- 020618 EMIG: updated for NFS threadsafety, V5R3 -->
|
|
<!-- 020624 RTHEIS: Add fclear() and fclear64(), V5R3 -->
|
|
<!-- 0205?? JET This file has undergone html cleanup -->
|
|
<!-- 020718 MFENLON: updated for QFileSvr.400 threadsafety, V5R3 -->
|
|
<!-- 050404 JTROUS: fix enums, no change flag, V5R4 -->
|
|
<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
|
|
</head>
|
|
<body>
|
|
<!--End Header Records --><!-- Java sync-link -->
|
|
<script language="Javascript" src="../rzahg/synch.js" type="text/javascript">
|
|
</script>
|
|
|
|
<a name="Top_Of_Page"></a>
|
|
|
|
<h2>lseek()--Set File Read/Write Offset</h2>
|
|
|
|
<div class="box" style="width: 80%;">
|
|
<br>
|
|
Syntax<br>
|
|
|
|
|
|
<pre>
|
|
#include <unistd.h>
|
|
|
|
off_t lseek(int <em>file_descriptor</em>, off_t <em>offset</em>, int <em>whence)</em>;
|
|
</pre>
|
|
|
|
Service Program Name: QP0LLIB1<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Default Public Authority: *USE<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Threadsafe: Conditional; see <a href="#HDRLSKUSAG">Usage Notes</a>.<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
</div>
|
|
|
|
<p>The <strong>lseek()</strong> function changes the current file offset to a
|
|
new position in the file. The new position is the given byte <em>offset</em>
|
|
from the position specified by <em>whence</em>. After you have used <strong>
|
|
lseek()</strong> to seek to a new location, the next I/O operation on the file
|
|
begins at that location.</p>
|
|
|
|
<p><strong>lseek()</strong> lets you specify new file offsets past the current
|
|
end of the file. If data is written at such a point, read operations in the gap
|
|
between this data and the old end of the file will return bytes containing
|
|
binary zeros (or bytes containing blanks in the QSYS.LIB and independent ASP
|
|
QSYS.LIB file systems). In other words, the gap is assumed to be filled with
|
|
zeros (or with blanks in the QSYS.LIB and independent ASP QSYS.LIB file
|
|
systems). Seeking past the end of a file, however, does not automatically
|
|
extend the length of the file. There must be a write operation before the file
|
|
is actually extended.</p>
|
|
|
|
<p>There are some important considerations for <strong>lseek()</strong> if the
|
|
O_TEXTDATA and O_CCSID flags were specified on the <strong>open()</strong>, the
|
|
file CCSID and open CCSID are not the same, and the converted data could expand
|
|
or contract:</p>
|
|
|
|
<ul>
|
|
<li>Making assumptions about data size and the current file offset is extremely
|
|
dangerous. For example, a file might have a physical size of 100 bytes, but
|
|
after an application has read 100 bytes from the file, the current file offset
|
|
may be only 50. To read the whole file, the application might have to read 200
|
|
bytes or more, depending on the CCSIDs involved. Therefore, <strong>
|
|
lseek()</strong> will only be allowed to change the current file offset to:<br>
|
|
<br>
|
|
<ul>
|
|
<li>The start of the file (<em>offset</em> 0, <em>whence</em> SEEK_SET)<br>
|
|
</li>
|
|
|
|
<li>The end of the file (<em>offset</em> 0, <em>whence</em> SEEK_END). In this
|
|
case, the function will return a calculated value based on the physical size of
|
|
the file, the CCSID of the file, and the CCSID of the open instance. This may
|
|
be different than the actual file offset.</li>
|
|
</ul>
|
|
|
|
<p>If any other combination of values is specified, <strong>lseek()</strong>
|
|
fails and <em>errno</em> is set to ENOTSUP.</p>
|
|
</li>
|
|
|
|
<li>Internally-buffered data from a read or write operation is discarded. See
|
|
<a href="read.htm">read()--Read from Descriptor</a> and <a href="write.htm">
|
|
write()--Write to Descriptor</a> for more information concerning internal
|
|
buffering of text data.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>The expected state for the current text conversion is reset to the initial
|
|
state. This consideration applies only when using a CCSID that can represent
|
|
data using more than one graphic character set or containing characters of
|
|
different byte lengths. Some CCSIDs require an escape or shift sequence to
|
|
signify a state change from one character set or byte length to another.
|
|
Failing to account for this consideration could lead to incorrect text
|
|
conversion if, for instance, a double-byte character at the new file offset was
|
|
treated as two single-byte characters by the conversion function.<br>
|
|
<br>
|
|
</li>
|
|
</ul>
|
|
|
|
<p>In the QSYS.LIB file and independent ASP QSYS.LIB file systems, you can seek
|
|
only to the beginning of a member while in text mode.</p>
|
|
|
|
<br>
|
|
<h3>Parameters</h3>
|
|
|
|
<dl>
|
|
<dt><strong><em>file_descriptor</em></strong></dt>
|
|
|
|
<dd>(Input) The file whose current file offset you want to change.<br>
|
|
</dd>
|
|
|
|
<dt><strong><em>offset</em></strong></dt>
|
|
|
|
<dd>(input) The amount (positive or negative) the byte offset is to be changed.
|
|
The sign indicates whether the offset is to be moved forward (positive) or
|
|
backward (negative).<br>
|
|
</dd>
|
|
|
|
<dt><strong><em>whence</em></strong></dt>
|
|
|
|
<dd>(Input) One of the following symbols (defined in the
|
|
<<strong>unistd.h</strong>> header file):
|
|
|
|
<dl compact>
|
|
<dt><em>SEEK_SET</em></dt>
|
|
|
|
<dd>The start of the file</dd>
|
|
|
|
<dt><em>SEEK_CUR</em></dt>
|
|
|
|
<dd>The current file offset in the file</dd>
|
|
|
|
<dt><em>SEEK_END</em></dt>
|
|
|
|
<dd>The end of the file</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>If bits in <em>whence</em> are set to values other than those defined above,
|
|
<strong>lseek()</strong> fails with the [EINVAL] error.</p>
|
|
|
|
<br>
|
|
<h3>Authorities</h3>
|
|
|
|
<p>No authorization is required. Authorization is verified during <strong>
|
|
open()</strong> or <strong>creat()</strong>.</p>
|
|
|
|
<br>
|
|
<h3>Return Value</h3>
|
|
|
|
<dl compact>
|
|
<dt><em>value</em></dt>
|
|
|
|
<dd><strong>lseek()</strong> was successful. The value returned is the new file
|
|
offset, measured in bytes from the beginning of the file.</dd>
|
|
|
|
<dt><em>-1</em></dt>
|
|
|
|
<dd><strong>lseek()</strong> was not successful. The <em>errno</em> global
|
|
variable is set to indicate the error.</dd>
|
|
</dl>
|
|
|
|
<br>
|
|
<h3><a name="HDRLSKERRS">Error Conditions</a></h3>
|
|
|
|
<p>If <strong>lseek()</strong> is not successful, <em>errno</em> usually
|
|
indicates one of the following errors. Under some conditions, <em>errno</em>
|
|
could indicate an error other than those listed here.</p>
|
|
|
|
<table cellpadding="5">
|
|
<!-- cols="25 75" -->
|
|
|
|
<tr>
|
|
<th align="left" valign="bottom">Error condition</th>
|
|
<th align="left" valign="bottom">Additional information</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EACCES">EACCES</a>]</em></td>
|
|
|
|
|
|
<td align="left" valign="top">
|
|
<p>If you are accessing a remote file through the Network File System, update
|
|
operations to file permissions at the server are not reflected at the client
|
|
until updates to data that is stored locally by the Network File System take
|
|
place. (Several options on the Add Mounted File System (ADDMFS) command
|
|
determine the time between refresh operations of local data.) Access to a
|
|
remote file may also fail due to different mappings of user IDs (UID) or group
|
|
IDs (GID) on the local and remote systems.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EAGAIN">EAGAIN</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EBADF">EBADF</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EBADFID">EBADFID</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EBUSY">EBUSY</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EDAMAGE">EDAMAGE</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EINVAL">EINVAL</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EIO">EIO</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENOENT">ENOENT</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENOSPC">ENOSPC</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENOSYSRSC">ENOSYSRSC</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENOTAVAIL">ENOTAVAIL</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENOTSAFE">ENOTSAFE</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENOTSUP">ENOTSUP</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EOVERFLOW">EOVERFLOW</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
<p>The resulting file offset would be a value that cannot be represented
|
|
correctly in a variable of type off_t (the offset is greater than 2GB minus 2
|
|
bytes).</p>
|
|
</td>
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ESPIPE">ESPIPE</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ESTALE">ESTALE</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
<p>If you are accessing a remote file through the Network File System, the file
|
|
may have been deleted at the server.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EUNKNOWN">EUNKNOWN</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>If interaction with a file server is required to access the object, <em>
|
|
errno</em> could indicate one of the following errors:</p>
|
|
|
|
<table cellpadding="5">
|
|
<!-- cols="25 75" -->
|
|
|
|
<tr>
|
|
<th align="left" valign="bottom">Error condition</th>
|
|
<th align="left" valign="bottom">Additional information</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EADDRNOTAVAIL">EADDRNOTAVAIL</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ECONNABORTED">ECONNABORTED</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ECONNREFUSED">ECONNREFUSED</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ECONNRESET">ECONNRESET</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EHOSTDOWN">EHOSTDOWN</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EHOSTUNREACH">EHOSTUNREACH</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENETDOWN">ENETDOWN</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENETRESET">ENETRESET</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ENETUNREACH">ENETUNREACH</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ESTALE">ESTALE</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
<p>If you are accessing a remote file through the Network File System, the file
|
|
may have been deleted at the server.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#ETIMEDOUT">ETIMEDOUT</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">
|
|
<em>[<a href="unix14.htm#EUNATCH">EUNATCH</a>]</em></td>
|
|
|
|
<td align="left" valign="top">
|
|
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br>
|
|
<br>
|
|
<h3>Error Messages</h3>
|
|
|
|
<p>The following messages may be sent from this function:</p>
|
|
|
|
<table width="100%">
|
|
<tr>
|
|
<th align="left" valign="top">Message ID</th>
|
|
<th align="left" valign="top">Error Message Text</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td width="15%" valign="top">CPE3418 E</td>
|
|
<td width="85%" valign="top">Possible APAR condition or hardware failure.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td valign="top">CPFA0D4 E</td>
|
|
<td valign="top">File system error occurred. Error number &1.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td valign="top">CPF3CF2 E</td>
|
|
<td valign="top">Error(s) occurred during running of &1 API.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td valign="top">CPF9872 E</td>
|
|
<td valign="top">Program or service program &1 in library &2 ended.
|
|
Reason code &3.</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br>
|
|
<h3><a name="HDRLSKUSAG">Usage Notes</a></h3>
|
|
|
|
<ol type="1">
|
|
<li>This function will fail with error code [ENOTSAFE] when all the following
|
|
conditions are true:<br>
|
|
<br>
|
|
<ul>
|
|
<li>Where multiple threads exist in the job.<br>
|
|
</li>
|
|
|
|
<li>The object on which this function is operating resides in a file system
|
|
that is not threadsafe. Only the following file systems are threadsafe for this
|
|
function:<br>
|
|
<br>
|
|
<ul>
|
|
<li>"Root" (/)</li>
|
|
|
|
<li>QOpenSys</li>
|
|
|
|
<li>User-defined</li>
|
|
|
|
<li>QNTC</li>
|
|
|
|
<li>QSYS.LIB</li>
|
|
|
|
<li>Independent ASP QSYS.LIB</li>
|
|
|
|
<li>QOPT</li>
|
|
|
|
<li>Network File System</li>
|
|
|
|
<li>QFileSvr.400</li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
|
|
<br>
|
|
</li>
|
|
|
|
<li>Network File System Differences
|
|
|
|
<p>Local access to remote files through the Network File System may produce
|
|
unexpected results due to conditions at the server. Once a file is open,
|
|
subsequent requests to perform operations on the file can fail because file
|
|
attributes are checked at the server on each request. If permissions on the
|
|
file are made more restrictive at the server or the file is unlinked or made
|
|
unavailable by the server for another client, your operation on an open file
|
|
descriptor will fail when the local Network File System receives these updates.
|
|
The local Network File System also impacts operations that retrieve file
|
|
attributes. Recent changes at the server may not be available at your client
|
|
yet, and old values may be returned from operations (several options on the Add
|
|
Mounted File System (ADDMFS) command determine the time between refresh
|
|
operations of local data).</p>
|
|
</li>
|
|
|
|
<li>QSYS.LIB and Independent ASP QSYS.LIB File System Differences
|
|
|
|
<p>This function is not supported for save files and will fail with error code
|
|
[ENOTSUP].</p>
|
|
</li>
|
|
|
|
<li>This function will fail with the [EOVERFLOW] error if the resulting file
|
|
offset would be a value that cannot be represented correctly in a variable of
|
|
type off_t (the offset is greater than 2 GB minus 2 bytes).<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>When you develop in C-based languages and an application is compiled with
|
|
the _LARGE_FILES macro defined, the <strong>lseek()</strong> API will be mapped
|
|
to a call to the <strong>lseek64()</strong> API. Additionally, the data type
|
|
off_t will be mapped to the type off64_t.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>Using this function with the write(), pwrite(), and pwrite64() functions on
|
|
the /dev/null or /dev/zero character special file will not result in the file
|
|
data size changing from zero.<br>
|
|
<br>
|
|
</li>
|
|
</ol>
|
|
|
|
<br>
|
|
<h3>Related Information</h3>
|
|
|
|
<ul>
|
|
<li>The <<strong>unistd.h</strong>> file (see <a href="unix13.htm">Header
|
|
Files for UNIX-Type Functions</a>)<br>
|
|
</li>
|
|
|
|
<li><a href="creat.htm">creat()</a>--Create or Rewrite File<br>
|
|
</li>
|
|
|
|
<li><a href="dup.htm">dup()</a>--Duplicate Open File Descriptor<br>
|
|
</li>
|
|
|
|
<li>
|
|
<a href="fclear.htm">fclear()</a>--Write (Binary Zeros) to Descriptor<br>
|
|
</li>
|
|
|
|
<li><a href="fclear64.htm">fclear64()</a>--Write (Binary Zeros) to Descriptor
|
|
(Large File Enabled)<br>
|
|
</li>
|
|
|
|
|
|
<li><a href="fcntl.htm">fcntl()</a>--Perform File Control Command<br>
|
|
</li>
|
|
|
|
<li><a href="lseek64.htm">lseek64()</a>--Set File Read/Write Offset (Large File
|
|
Enabled)<br>
|
|
</li>
|
|
|
|
<li><a href="open.htm">open()</a>--Open File<br>
|
|
</li>
|
|
|
|
<li><a href="pread.htm">pread()</a>--Read from Descriptor with Offset<br>
|
|
</li>
|
|
|
|
<li><a href="pread64.htm">pread64()</a>--Read from Descriptor with Offset
|
|
(large file enabled)<br>
|
|
</li>
|
|
|
|
<li><a href="pwrite.htm">pwrite()</a>--Write to Descriptor with Offset<br>
|
|
</li>
|
|
|
|
<li><a href="pwrite64.htm">pwrite64()</a>--Write to Descriptor with Offset
|
|
(large file enabled)<br>
|
|
</li>
|
|
|
|
<li><a href="read.htm">read()</a>--Read from Descriptor<br>
|
|
</li>
|
|
|
|
<li><a href="write.htm">write()</a>--Write to Descriptor</li>
|
|
</ul>
|
|
|
|
<br>
|
|
<h3>Example</h3>
|
|
|
|
<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
|
|
for information pertaining to code examples.</p>
|
|
|
|
<p>The following example positions a file (that has at least 11 bytes) to an
|
|
offset of 10 bytes before the end of the file:</p>
|
|
|
|
<pre>
|
|
lseek(file_descriptor,-<samp>1</samp>0,SEEK_END);
|
|
</pre>
|
|
|
|
<br>
|
|
<hr>
|
|
API introduced: V4R4
|
|
|
|
<hr>
|
|
<center>
|
|
<table cellpadding="2" cellspacing="2">
|
|
<tr align="center">
|
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
|
|
"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a></td>
|
|
</tr>
|
|
</table>
|
|
</center>
|
|
</body>
|
|
</html>
|
|
|