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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>getpwuid</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_005_704"> </a>NAME</h4><blockquote>getpwuid, getpwuid_r - search user database for a user ID</blockquote><h4><a name = "tag_000_005_705"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="systypes.h.html">sys/types.h</a>>#include <<a href="pwd.h.html">pwd.h</a>>struct passwd *getpwuid(uid_t <i>uid</i>);int getpwuid_r(uid_t <i>uid</i>, struct passwd *<i>pwd</i>, char *<i>buffer</i>, size_t <i>bufsize</i>, struct passwd **<i>result</i>);</code></pre></blockquote><h4><a name = "tag_000_005_706"> </a>DESCRIPTION</h4><blockquote>The<i>getpwuid()</i>function searches the user database for an entry with a matching<i>uid</i>.<p>The<i>getpwuid()</i>interface need not be reentrant.<p>The<i>getpwuid_r()</i>function updates the<b>passwd</b>structure pointed to by<i>pwd</i>and stores a pointer to that structureat the location pointed to by<i>result.</i>The structure will contain an entryfrom the user database with a matching<i>uid</i>.Storage referenced by the structure is allocatedfrom the memory provided with the<i>buffer</i>parameter, which is<i>bufsize</i>characters in size.The maximum size needed for this buffer can be determined with the{_SC_GETPW_R_SIZE_MAX}<i><a href="sysconf.html">sysconf()</a></i>parameter.A NULL pointer is returned at the location pointed to by<i>result</i>on error or if the requested entry is not found.<p>Applications wishing to check for error situations should set<i>errno</i>to 0 before calling<i>getpwuid()</i>.If<i>getpwuid()</i>returns a null pointer and<i>errno</i>is set to non-zero, an error occurred.</blockquote><h4><a name = "tag_000_005_707"> </a>RETURN VALUE</h4><blockquote>The<i>getpwuid()</i>function returns a pointer to a<b>struct passwd</b>with the structure as defined in<i><a href="pwd.h.html"><pwd.h></a></i>with a matching entry if found.A null pointer is returned if the requested entryis not found, or an error occurs.On error,<i>errno</i>is set to indicate the error.<p>The return value may point to a static area which is overwrittenby a subsequent call to<i><a href="getpwent.html">getpwent()</a></i>,<i><a href="getpwnam.html">getpwnam()</a></i>or<i>getpwuid()</i>.<p>If successful, the<i>getpwuid_r()</i>function returns zero.Otherwise, an error number is returned to indicate the error.</blockquote><h4><a name = "tag_000_005_708"> </a>ERRORS</h4><blockquote>The<i>getpwuid()</i>function may fail if:<br><dl compact><dt>[EIO]<dd>An I/O error has occurred.<dt>[EINTR]<dd>A signal was caught during<i>getpwuid()</i>.<dt>[EMFILE]<dd>{OPEN_MAX} file descriptors are currently open in the calling process.<dt>[ENFILE]<dd>The maximum allowable number of files is currently open in the system.</dl><p>The <i>getpwuid_r()</i>function may fail if:<dl compact><dt>[ERANGE]<dd>Insufficient storage was supplied via<i>buffer</i>and<i>bufsize</i>to contain the data to be referenced by the resulting<b>passwd</b>structure.</dl></blockquote><h4><a name = "tag_000_005_709"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_005_710"> </a>APPLICATION USAGE</h4><blockquote>Three names associated with the current process can be determined:<i>getpwuid</i>(<i>geteuid</i>())returns the name associated with the effective user ID of the process;<i><a href="getlogin.html">getlogin()</a></i>returns the name associated with the current login activity; and<i>getpwuid</i>(<i>getuid</i>())returns the name associated with the real user ID of the process.</blockquote><h4><a name = "tag_000_005_711"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_005_712"> </a>SEE ALSO</h4><blockquote><i><a href="getpwnam.html">getpwnam()</a></i>,<i><a href="geteuid.html">geteuid()</a></i>,<i><a href="getuid.html">getuid()</a></i>,<i><a href="getlogin.html">getlogin()</a></i>,<i><a href="limits.h.html"><limits.h></a></i>,<i><a href="pwd.h.html"><pwd.h></a></i>,<i><a href="systypes.h.html"><sys/types.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote><i>getpwuid()</i> derived from System V Release 2.0.<P><i>getpwuid_r()</i> derived from the POSIX Threads Extension (1003.1c-1995).</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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