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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>lchown</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="lchown"></a> <a name="tag_03_327"></a><!-- lchown --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_327_01"></a>NAME</h4><blockquote>lchown - change the owner and group of a symbolic link</blockquote><h4><a name="tag_03_327_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/unistd.h.html">unistd.h</a>><br><br> int lchown(const char *</tt><i>path</i><tt>, uid_t</tt> <i>owner</i><tt>, gid_t</tt> <i>group</i><tt>); <img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div><tt><br></tt></blockquote><h4><a name="tag_03_327_03"></a>DESCRIPTION</h4><blockquote><p>The <i>lchown</i>() function shall be equivalent to <a href="../functions/chown.html"><i>chown</i>()</a>, except in the casewhere the named file is a symbolic link. In this case, <i>lchown</i>() shall change the ownership of the symbolic link file itself,while <a href="../functions/chown.html"><i>chown</i>()</a> changes the ownership of the file or directory to which the symboliclink refers.</p></blockquote><h4><a name="tag_03_327_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, <i>lchown</i>() shall return 0. Otherwise, it shall return -1 and set <i>errno</i> to indicate anerror.</p></blockquote><h4><a name="tag_03_327_05"></a>ERRORS</h4><blockquote><p>The <i>lchown</i>() function shall fail if:</p><dl compact><dt>[EACCES]</dt><dd>Search permission is denied on a component of the path prefix of <i>path</i>.</dd><dt>[EINVAL]</dt><dd>The owner or group ID is not a value supported by the implementation.</dd><dt>[ELOOP]</dt><dd>A loop exists in symbolic links encountered during resolution of the <i>path</i> argument.</dd><dt>[ENAMETOOLONG]</dt><dd>The length of a pathname exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.</dd><dt>[ENOENT]</dt><dd>A component of <i>path</i> does not name an existing file or <i>path</i> is an empty string.</dd><dt>[ENOTDIR]</dt><dd>A component of the path prefix of <i>path</i> is not a directory.</dd><dt>[EOPNOTSUPP]</dt><dd>The <i>path</i> argument names a symbolic link and the implementation does not support setting the owner or group of a symboliclink.</dd><dt>[EPERM]</dt><dd>The effective user ID does not match the owner of the file and the process does not have appropriate privileges.</dd><dt>[EROFS]</dt><dd>The file resides on a read-only file system.</dd></dl><p>The <i>lchown</i>() function may fail if:</p><dl compact><dt>[EIO]</dt><dd>An I/O error occurred while reading or writing to the file system.</dd><dt>[EINTR]</dt><dd>A signal was caught during execution of the function.</dd><dt>[ELOOP]</dt><dd>More than {SYMLOOP_MAX} symbolic links were encountered during resolution of the <i>path</i> argument.</dd><dt>[ENAMETOOLONG]</dt><dd>Pathname resolution of a symbolic link produced an intermediate result whose length exceeds {PATH_MAX}.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_327_06"></a>EXAMPLES</h4><blockquote><h5><a name="tag_03_327_06_01"></a>Changing the Current Owner of a File</h5><p>The following example shows how to change the ownership of the symbolic link named <b>/modules/pass1</b> to the user IDassociated with "jones" and the group ID associated with "cnd".</p><p>The numeric value for the user ID is obtained by using the <a href="../functions/getpwnam.html"><i>getpwnam</i>()</a> function.The numeric value for the group ID is obtained by using the <a href="../functions/getgrnam.html"><i>getgrnam</i>()</a>function.</p><pre><tt>#include <sys/types.h>#include <unistd.h>#include <pwd.h>#include <grp.h><br>struct passwd *pwd;struct group *grp;char *path = "/modules/pass1";...pwd = getpwnam("jones");grp = getgrnam("cnd");lchown(path, pwd->pw_uid, grp->gr_gid);</tt></pre></blockquote><h4><a name="tag_03_327_07"></a>APPLICATION USAGE</h4><blockquote><p>On implementations which support symbolic links as directory entries rather than files, <i>lchown</i>() may fail.</p></blockquote><h4><a name="tag_03_327_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_327_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_327_10"></a>SEE ALSO</h4><blockquote><p><a href="chown.html"><i>chown</i>()</a>, <a href="symlink.html"><i>symlink</i>()</a>, the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/unistd.h.html"><i><unistd.h></i></a></p></blockquote><h4><a name="tag_03_327_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 4, Version 2.</p></blockquote><h4><a name="tag_03_327_12"></a>Issue 5</h4><blockquote><p>Moved from X/OPEN UNIX extension to BASE.</p></blockquote><h4><a name="tag_03_327_13"></a>Issue 6</h4><blockquote><p>The wording of the mandatory [ELOOP] error condition is updated, and a second optional [ELOOP] error condition is added.</p><p>The Open Group Base Resolution bwg2001-013 is applied, adding wording to the APPLICATION USAGE.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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