unlink.html
来自「unix 下的C开发手册,还用详细的例程。」· HTML 代码 · 共 170 行
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>unlink</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_010_280"> </a>NAME</h4><blockquote>unlink - remove a directory entry</blockquote><h4><a name = "tag_000_010_281"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="unistd.h.html">unistd.h</a>>int unlink(const char *<i>path</i>);</code></pre></blockquote><h4><a name = "tag_000_010_282"> </a>DESCRIPTION</h4><blockquote>The<i>unlink()</i>function removes a link to a file.If<i>path</i>names a symbolic link,<i>unlink()</i>removes the symbolic link named by<i>path</i>and does not affect any file or directory named by the contents of thesymbolic link. Otherwise,<i>unlink()</i>removes the link named by the pathname pointed to by<i>path</i>and decrements the link count of the file referenced by the link.<p>When the file's link count becomes 0 and no process has thefile open, the space occupied by the file will be freed and thefile will no longer be accessible.If one or more processes have the file open when the last link isremoved, the link will be removed before<i>unlink()</i>returns, butthe removal of the file contents will be postponed until allreferences to the file are closed.<p>The<i>path</i>argument must not name a directory unless the process hasappropriate privileges and the implementation supports using<i>unlink()</i>on directories.<p>Upon successful completion,<i>unlink()</i>will mark for update the<i>st_ctime</i>and<i>st_mtime</i>fields of the parent directory. Also, if the file's link count is not 0, the<i>st_ctime</i>field of the file will be marked for update.</blockquote><h4><a name = "tag_000_010_283"> </a>RETURN VALUE</h4><blockquote>Upon successful completion, 0 is returned. Otherwise, -1 is returned and<i>errno</i>is set to indicate the error.If -1 is returned, the named file will not be changed.</blockquote><h4><a name = "tag_000_010_284"> </a>ERRORS</h4><blockquote>The<i>unlink()</i>function will fail and not unlink the file if:<dl compact><dt>[EACCES]<dd>Search permission is denied for a component of thepath prefix, orwrite permission is denied on the directory containing the directory entryto be removed.<dt>[EBUSY]<dd>The file named by the<i>path</i>argument cannot be unlinked because it is being used by the systemor another process and the implementation considers this an error.<dt>[ELOOP]<dd>Too many symbolic links were encountered in resolving <i>path</i>.<dt>[ENAMETOOLONG]<dd>The length of the<i>path</i>argument exceeds {PATH_MAX} or a pathname component is longer than{NAME_MAX}.<dt>[ENOENT]<dd>A component of <i>path</i> does not name an existing fileor <i>path</i> is an empty string.<dt>[ENOTDIR]<dd>A component of the path prefix is not a directory.<dt>[EPERM]<dd>The file named by<i>path</i>is a directory, and either the calling process does not haveappropriate privileges, or the implementation prohibits using<i>unlink()</i>on directories.<dt>[EPERM] or [EACCES]<dd>The S_ISVTX flag is set on the directory containing the file referred to bythe <i>path</i> argument and the caller is not the file owner, nor is thecaller the directory owner, nor does the caller have appropriate privileges.<dt>[EROFS]<dd>The directory entry to be unlinked is part of a read-only file system.</dl><p>The<i>unlink()</i>function may fail and not unlink the file if:<dl compact><dt>[EBUSY]<dd>The file named by<i>path</i>is a named STREAM.<dt>[ENAMETOOLONG]<dd>Pathname resolution of a symbolic link produced an intermediate result whoselength exceeds {PATH_MAX}.<dt>[ETXTBSY]<dd>The entry to be unlinked is the last directory entry toa pure procedure (shared text) file that is being executed.</dl></blockquote><h4><a name = "tag_000_010_285"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_010_286"> </a>APPLICATION USAGE</h4><blockquote>Applications should use<i><a href="rmdir.html">rmdir()</a></i>to remove a directory.</blockquote><h4><a name = "tag_000_010_287"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_010_288"> </a>SEE ALSO</h4><blockquote><i><a href="close.html">close()</a></i>,<i><a href="link.html">link()</a></i>,<i><a href="remove.html">remove()</a></i>,<i><a href="rmdir.html">rmdir()</a></i>,<i><a href="unistd.h.html"><unistd.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote>Derived from Issue 1 of the SVID.</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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