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<title>fchmod()--Change File Authorizations by Descriptor</title>
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<h2>fchmod()--Change File Authorizations by Descriptor</h2>
<div class="box" style="width: 70%;">
<br>
&nbsp;&nbsp;Syntax<br>
<pre>
#include &lt;sys/stat.h&gt;
int fchmod(int <em>fildes</em>, mode_t <em>mode</em>);
</pre>
&nbsp;&nbsp;Service Program Name: QP0LLIB1<br>
<!-- iddvc RMBR -->
<br>
&nbsp;&nbsp;Default Public Authority: *USE<br>
<!-- iddvc RMBR -->
<br>
&nbsp;&nbsp;Threadsafe: Conditional; see <a href="chmod.htm#HDRCHMODUS">Usage Notes</a> for
chmod().<br>
<!-- iddvc RMBR -->
<br>
</div>
<p>The <strong>fchmod()</strong> function changes S_ISUID, S_ISGID,
S_ISVTX,
and the
permission bits of the open file or directory, identified by <em>fildes</em>,
to the corresponding bits specified in <em>mode</em>. <strong>
fchmod()</strong> has no effect on file descriptions for files that are open at
the time <strong>fchmod()</strong> is called.</p>
<p><strong>fchmod()</strong> marks for update the change time of the file.</p>
<p>If the file is checked out by another user (someone other than the user
profile of the current job), <strong>fchmod()</strong> fails with the [EBUSY]
error.</p>
<br>
<h3>Parameters</h3>
<dl>
<dt><strong><em>fildes</em></strong></dt>
<dd>(Input) The file descriptor of the file.<br>
</dd>
<dt><strong><em>mode</em></strong></dt>
<dd>(Input) Bits that define S_ISUID, S_ISGID,
S_ISVTX,
and the access permissions of
the file.</dd>
</dl>
<p>The <em>mode</em> argument is created with one of the symbols defined in the
&lt;<strong>sys/stat.h</strong>&gt; header file. For more information on the
symbols, refer to <a href="chmod.htm">chmod()--Change File
Authorizations</a>.</p>
<p>If bits other than the bits listed above are set in <em>mode</em>, <strong>
fchmod()</strong> returns the [EINVAL] error.</p>
<br>
<h3>Authorities</h3>
<strong>Note:</strong> Adopted authority is not used.
<p><strong><a name="TBLAFCHMO">Authorization Required for fchmod() (excluding
QDLS)</a></strong><br>
</p>
<table border cellpadding="5" width="80%">
<tr>
<th align="left" valign="bottom">Object Referred to</th>
<th align="left" valign="bottom">Authority Required</th>
<th align="left" valign="bottom">errno</th>
</tr>
<tr>
<td align="left" valign="top" width="45%">Object</td>
<td align="left" valign="top" width="45%">Owner (see <strong>
Note</strong>)</td>
<td align="left" valign="top" width="10%">EPERM</td>
</tr>
<tr>
<td align="left" valign="top"><strong>Note:</strong> You do not need the listed
authority if you have *ALLOBJ special authority.</td>
</tr>
</table>
<br>
<p><strong><a name="TBLAFCHMO3">Authorization Required for fchmod() in the QDLS
File System</a></strong><br>
</p>
<table border cellpadding="5" width="80%">
<tr>
<th align="left" valign="bottom">Object Referred to</th>
<th align="left" valign="bottom">Authority Required</th>
<th align="left" valign="bottom">errno</th>
</tr>
<tr>
<td align="left" valign="top" width="45%">Object</td>
<td align="left" valign="top" width="45%">Owner or *ALL</td>
<td align="left" valign="top" width="10%">EACCES</td>
</tr>
</table>
<br>
<h3>Return Value</h3>
<dl compact>
<dt><em>0</em></dt>
<dd><strong>fchmod()</strong> was successful.</dd>
<dt><em>-1</em></dt>
<dd><strong>fchmod()</strong> was not successful. The <em>errno</em> global
variable is set to indicate the error.</dd>
</dl>
<br>
<h3>Error Conditions</h3>
<p>If <strong>fchmod()</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">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EBADF">EBADF</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EBADFID">EBADFID</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EBADNAME">EBADNAME</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EBUSY">EBUSY</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ECONVERT">ECONVERT</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EDAMAGE">EDAMAGE</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EINTR">EINTR</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EINVAL">EINVAL</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EIO">EIO</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EJRNDAMAGE">EJRNDAMAGE</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EJRNENTTOOLONG">EJRNENTTOOLONG</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EJRNINACTIVE">EJRNINACTIVE</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EJRNRCVSPC">EJRNRCVSPC</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr><tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENAMETOOLONG">ENAMETOOLONG</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENEWJRN">ENEWJRN</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENEWJRNRCV">ENEWJRNRCV</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOENT">ENOENT</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOSPC">ENOSPC</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOSYS">ENOSYS</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOSYSRSC">ENOSYSRSC</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOTAVAIL">ENOTAVAIL</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOTDIR">ENOTDIR</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOTSAFE">ENOTSAFE</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENOTSUP">ENOTSUP</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EPERM">EPERM</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EROOBJ">EROOBJ</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</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">
&nbsp;
</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">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ECONNABORTED">ECONNABORTED</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ECONNREFUSED">ECONNREFUSED</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ECONNRESET">ECONNRESET</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EHOSTDOWN">EHOSTDOWN</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EHOSTUNREACH">EHOSTUNREACH</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENETDOWN">ENETDOWN</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENETRESET">ENETRESET</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#ENETUNREACH">ENETUNREACH</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</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">
&nbsp;
</td>
</tr>
<tr>
<td align="left" valign="top">
<em>[<a href="unix14.htm#EUNATCH">EUNATCH</a>]</em></td>
<td align="left" valign="top">
&nbsp;
</td>
</tr>
</table>
<br>
<br>
<h3>Error Messages</h3>
<p>The following messages may be sent from this API:</p>
<table width="100%" cellpadding="5">
<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 &amp;1.</td>
</tr>
<tr>
<td valign="top">CPF3CF2 E</td>
<td valign="top">Error(s) occurred during running of &amp;1 API.</td>
</tr>
<tr>
<td valign="top">CPF9872 E</td>
<td valign="top">Program or service program &amp;1 in library &amp;2 ended.
Reason code &amp;3.</td>
</tr>
</table>
<br>
<h3>Related Information</h3>
<ul>
<li>The &lt;<strong>sys/stat.h</strong>&gt; file (see <a href="unix13.htm">
Header Files for UNIX-Type Functions</a>)<br>
</li>
<li><a href="chmod.htm">chmod()</a>--Change File Authorizations<br>
</li>
<li><a href="chown.htm">chown()</a>--Change Owner and Group of File<br>
</li>
<li><a href="fchown.htm">fchown()</a>--Change Owner and Group of File by
Descriptor<br>
</li>
<li><a href="mkdir.htm">mkdir()</a>--Make Directory<br>
</li>
<li><a href="open.htm">open()</a>--Open File<br>
</li>
<li><a href="stat.htm">stat()</a>--Get File Information</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 changes a file permission:</p>
<pre>
#include &lt;stdio.h&gt;
#include &lt;fcntl.h&gt;
#include &lt;sys/stat.h&gt;
#include &lt;sys/types.h&gt;
main() {
char fn[]="temp.file";
int file_descriptor;
struct stat info;
if ((file_descriptor = creat(fn, S_IWUSR)) &lt; 0)
perror("creat() error");
else {
if (stat(fn, &amp;info)!= 0)
perror("stat() error");
else {
printf("original permissions were: %08o\n", info.st_mode);
}
if (fchmod(file_descriptor, S_IRWXU|S_IRWXG) != 0)
perror("fchmod() error");
else {
if (stat(fn, &amp;info)!= 0)
perror("stat() error");
else {
printf("after fchmod(), permissions are: %08o\n", info.st_mode);
}
}
if (close(file_descriptor)!= 0)
perror("close() error");
if (unlink(fn)!= 0)
perror("unlink() error");
}
}
</pre>
<p><strong>Output:</strong></p>
<pre>
original permissions were: 00100200
after fchmod(), permissions are: 00100770
</pre>
<br>
<hr>
API introduced: V3R1
<hr>
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