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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) 2001-2003 The Open Group, All Rights Reserved --><title>fstat</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="fstat"></a> <a name="tag_03_193"></a><!-- fstat --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_193_01"></a>NAME</h4><blockquote>fstat - get file status</blockquote><h4><a name="tag_03_193_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/sys/stat.h.html">sys/stat.h</a>><br><br> int fstat(int</tt> <i>fildes</i><tt>, struct stat *</tt><i>buf</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_193_03"></a>DESCRIPTION</h4><blockquote><p>The <i>fstat</i>() function shall obtain information about an open file associated with the file descriptor <i>fildes</i>, andshall write it to the area pointed to by <i>buf</i>.</p><p><sup>[<a href="javascript:open_code('SHM')">SHM</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">If <i>fildes</i> references a shared memory object, the implementation shall update in the <b>stat</b> structure pointed to by the<i>buf</i> argument only the <i>st_uid</i>, <i>st_gid</i>, <i>st_size</i>, and <i>st_mode</i> fields, and only the S_IRUSR,S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file permission bits need be valid. The implementation may update other fields andflags. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p><sup>[<a href="javascript:open_code('TYM')">TYM</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">If <i>fildes</i> references a typed memory object, the implementation shall update in the <b>stat</b> structure pointed to by the<i>buf</i> argument only the <i>st_uid</i>, <i>st_gid</i>, <i>st_size</i>, and <i>st_mode</i> fields, and only the S_IRUSR,S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file permission bits need be valid. The implementation may update other fields andflags. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p>The <i>buf</i> argument is a pointer to a <b>stat</b> structure, as defined in <a href="../basedefs/sys/stat.h.html"><i><sys/stat.h></i></a>, into which information is placed concerning the file.</p><p>The structure members <i>st_mode</i>, <i>st_ino</i>, <i>st_dev</i>, <i>st_uid</i>, <i>st_gid</i>, <i>st_atime</i>,<i>st_ctime</i>, and <i>st_mtime</i> shall have meaningful values for all other file types defined in this volume ofIEEE Std 1003.1-2001. The value of the member <i>st_nlink</i> shall be set to the number of links to the file.</p><p>An implementation that provides additional or alternative file access control mechanisms may, under implementation-definedconditions, cause <i>fstat</i>() to fail.</p><p>The <i>fstat</i>() function shall update any time-related fields as described in the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap04.html#tag_04_07">Section 4.7, File Times Update</a>, before writinginto the <b>stat</b> structure.</p></blockquote><h4><a name="tag_03_193_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and <i>errno</i> set to indicate the error.</p></blockquote><h4><a name="tag_03_193_05"></a>ERRORS</h4><blockquote><p>The <i>fstat</i>() function shall fail if:</p><dl compact><dt>[EBADF]</dt><dd>The <i>fildes</i> argument is not a valid file descriptor.</dd><dt>[EIO]</dt><dd>An I/O error occurred while reading from the file system.</dd><dt>[EOVERFLOW]</dt><dd>The file size in bytes or the number of blocks allocated to the file or the file serial number cannot be represented correctlyin the structure pointed to by <i>buf</i>.</dd></dl><p>The <i>fstat</i>() function may fail if:</p><dl compact><dt>[EOVERFLOW]</dt><dd>One of the values is too large to store into the structure pointed to by the <i>buf</i> argument.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_193_06"></a>EXAMPLES</h4><blockquote><h5><a name="tag_03_193_06_01"></a>Obtaining File Status Information</h5><p>The following example shows how to obtain file status information for a file named <b>/home/cnd/mod1</b>. The structure variable<i>buffer</i> is defined for the <b>stat</b> structure. The <b>/home/cnd/mod1</b> file is opened with read/write privileges and ispassed to the open file descriptor <i>fildes</i>.</p><pre><tt>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h><br>struct stat buffer;int status;...fildes = open("/home/cnd/mod1", O_RDWR);status = fstat(fildes, &buffer);</tt></pre></blockquote><h4><a name="tag_03_193_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_193_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_193_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_193_10"></a>SEE ALSO</h4><blockquote><p><a href="lstat.html"><i>lstat</i>()</a> , <a href="stat.html"><i>stat</i>()</a> , the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/sys/stat.h.html"><i><sys/stat.h></i></a>, <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a></p></blockquote><h4><a name="tag_03_193_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 1. Derived from Issue 1 of the SVID.</p></blockquote><h4><a name="tag_03_193_12"></a>Issue 5</h4><blockquote><p>The DESCRIPTION is updated for alignment with the POSIX Realtime Extension.</p><p>Large File Summit extensions are added.</p></blockquote><h4><a name="tag_03_193_13"></a>Issue 6</h4><blockquote><p>In the SYNOPSIS, the optional include of the <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> header isremoved.</p><p>The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:</p><ul><li><p>The requirement to include <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> has been removed. Although <ahref="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> was required for conforming implementations of previous POSIXspecifications, it was not required for UNIX applications.</p></li><li><p>The [EIO] mandatory error condition is added.</p></li><li><p>The [EOVERFLOW] mandatory error condition is added. This change is to support large files.</p></li><li><p>The [EOVERFLOW] optional error condition is added.</p></li></ul><p>The DESCRIPTION is updated for alignment with IEEE Std 1003.1j-2000 by specifying that shared memory object semanticsapply to typed memory objects.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr><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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