arm-2011.03/share/doc/arm-arm-none-linux-gnueabi/html/libc/Lookup-User.html - nest-cam/v366/arm-none-linux-gnueabi-i686-pc-linux-gnu - Git at Google

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 <p>
 Next:&nbsp;<a rel="next" accesskey="n" href="Scanning-All-Users.html#Scanning-All-Users">Scanning All Users</a>,
 Previous:&nbsp;<a rel="previous" accesskey="p" href="User-Data-Structure.html#User-Data-Structure">User Data Structure</a>,
 Up:&nbsp;<a rel="up" accesskey="u" href="User-Database.html#User-Database">User Database</a>
 <hr>
 </div>

 <h4 class="subsection">29.13.2 Looking Up One User</h4>

 <p><a name="index-converting-user-ID-to-user-name-3393"></a><a name="index-converting-user-name-to-user-ID-3394"></a>
 You can search the system user database for information about a
 specific user using <code>getpwuid</code> or <code>getpwnam</code>.  These
 functions are declared in <samp><span class="file">pwd.h</span></samp>.

 <!-- pwd.h -->
 <!-- POSIX.1 -->
 <div class="defun">
 &mdash; Function: struct passwd * <b>getpwuid</b> (<var>uid_t uid</var>)<var><a name="index-getpwuid-3395"></a></var><br>
 <blockquote><p>This function returns a pointer to a statically-allocated structure
 containing information about the user whose user ID is <var>uid</var>.  This
 structure may be overwritten on subsequent calls to <code>getpwuid</code>.

         <p>A null pointer value indicates there is no user in the data base with
 user ID <var>uid</var>.
 </p></blockquote></div>

 <!-- pwd.h -->
 <!-- POSIX.1c -->
 <div class="defun">
 &mdash; Function: int <b>getpwuid_r</b> (<var>uid_t uid, struct passwd *result_buf, char *buffer, size_t buflen, struct passwd **result</var>)<var><a name="index-getpwuid_005fr-3396"></a></var><br>
 <blockquote><p>This function is similar to <code>getpwuid</code> in that it returns
 information about the user whose user ID is <var>uid</var>.  However, it
 fills the user supplied structure pointed to by <var>result_buf</var> with
 the information instead of using a static buffer.  The first
 <var>buflen</var> bytes of the additional buffer pointed to by <var>buffer</var>
 are used to contain additional information, normally strings which are
 pointed to by the elements of the result structure.

         <p>If a user with ID <var>uid</var> is found, the pointer returned in
 <var>result</var> points to the record which contains the wanted data (i.e.,
 <var>result</var> contains the value <var>result_buf</var>).  If no user is found
 or if an error occurred, the pointer returned in <var>result</var> is a null
 pointer.  The function returns zero or an error code.  If the buffer
 <var>buffer</var> is too small to contain all the needed information, the
 error code <code>ERANGE</code> is returned and <var>errno</var> is set to
 <code>ERANGE</code>.
 </p></blockquote></div>

 <!-- pwd.h -->
 <!-- POSIX.1 -->
 <div class="defun">
 &mdash; Function: struct passwd * <b>getpwnam</b> (<var>const char *name</var>)<var><a name="index-getpwnam-3397"></a></var><br>
 <blockquote><p>This function returns a pointer to a statically-allocated structure
 containing information about the user whose user name is <var>name</var>.
 This structure may be overwritten on subsequent calls to
 <code>getpwnam</code>.

         <p>A null pointer return indicates there is no user named <var>name</var>.
 </p></blockquote></div>

 <!-- pwd.h -->
 <!-- POSIX.1c -->
 <div class="defun">
 &mdash; Function: int <b>getpwnam_r</b> (<var>const char *name, struct passwd *result_buf, char *buffer, size_t buflen, struct passwd **result</var>)<var><a name="index-getpwnam_005fr-3398"></a></var><br>
 <blockquote><p>This function is similar to <code>getpwnam</code> in that is returns
 information about the user whose user name is <var>name</var>.  However, like
 <code>getpwuid_r</code>, it fills the user supplied buffers in
 <var>result_buf</var> and <var>buffer</var> with the information instead of using
 a static buffer.

         <p>The return values are the same as for <code>getpwuid_r</code>.
 </p></blockquote></div>

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	<title>Lookup User - The GNU C Library</title>
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	<!--
	This file documents the GNU C library.

	This is Edition 0.12, last updated 2007-10-27,
	of `The GNU C Library Reference Manual', for version
	2.8 (Sourcery G++ Lite 2011.03-41).

	Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002,
	2003, 2007, 2008, 2010 Free Software Foundation, Inc.

	Permission is granted to copy, distribute and/or modify this document
	under the terms of the GNU Free Documentation License, Version 1.3 or
	any later version published by the Free Software Foundation; with the
	Invariant Sections being ``Free Software Needs Free Documentation''
	and ``GNU Lesser General Public License'', the Front-Cover texts being
	``A GNU Manual'', and with the Back-Cover Texts as in (a) below. A
	copy of the license is included in the section entitled "GNU Free
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	<div class="node">
	<a name="Lookup-User"></a>
	<p>
	Next: <a rel="next" accesskey="n" href="Scanning-All-Users.html#Scanning-All-Users">Scanning All Users</a>,
	Previous: <a rel="previous" accesskey="p" href="User-Data-Structure.html#User-Data-Structure">User Data Structure</a>,
	Up: <a rel="up" accesskey="u" href="User-Database.html#User-Database">User Database</a>
	<hr>
	</div>

	<h4 class="subsection">29.13.2 Looking Up One User</h4>

	<p><a name="index-converting-user-ID-to-user-name-3393"></a><a name="index-converting-user-name-to-user-ID-3394"></a>
	You can search the system user database for information about a
	specific user using <code>getpwuid</code> or <code>getpwnam</code>. These
	functions are declared in <samp><span class="file">pwd.h</span></samp>.

	<!-- pwd.h -->
	<!-- POSIX.1 -->
	<div class="defun">
	— Function: struct passwd * <b>getpwuid</b> (<var>uid_t uid</var>)<var><a name="index-getpwuid-3395"></a></var><br>
	<blockquote><p>This function returns a pointer to a statically-allocated structure
	containing information about the user whose user ID is <var>uid</var>. This
	structure may be overwritten on subsequent calls to <code>getpwuid</code>.

	<p>A null pointer value indicates there is no user in the data base with
	user ID <var>uid</var>.
	</p></blockquote></div>

	<!-- pwd.h -->
	<!-- POSIX.1c -->
	<div class="defun">
	— Function: int <b>getpwuid_r</b> (<var>uid_t uid, struct passwd result_buf, char buffer, size_t buflen, struct passwd **result</var>)<var><a name="index-getpwuid_005fr-3396"></a></var><br>
	<blockquote><p>This function is similar to <code>getpwuid</code> in that it returns
	information about the user whose user ID is <var>uid</var>. However, it
	fills the user supplied structure pointed to by <var>result_buf</var> with
	the information instead of using a static buffer. The first
	<var>buflen</var> bytes of the additional buffer pointed to by <var>buffer</var>
	are used to contain additional information, normally strings which are
	pointed to by the elements of the result structure.

	<p>If a user with ID <var>uid</var> is found, the pointer returned in
	<var>result</var> points to the record which contains the wanted data (i.e.,
	<var>result</var> contains the value <var>result_buf</var>). If no user is found
	or if an error occurred, the pointer returned in <var>result</var> is a null
	pointer. The function returns zero or an error code. If the buffer
	<var>buffer</var> is too small to contain all the needed information, the
	error code <code>ERANGE</code> is returned and <var>errno</var> is set to
	<code>ERANGE</code>.
	</p></blockquote></div>

	<!-- pwd.h -->
	<!-- POSIX.1 -->
	<div class="defun">
	— Function: struct passwd * <b>getpwnam</b> (<var>const char *name</var>)<var><a name="index-getpwnam-3397"></a></var><br>
	<blockquote><p>This function returns a pointer to a statically-allocated structure
	containing information about the user whose user name is <var>name</var>.
	This structure may be overwritten on subsequent calls to
	<code>getpwnam</code>.

	<p>A null pointer return indicates there is no user named <var>name</var>.
	</p></blockquote></div>

	<!-- pwd.h -->
	<!-- POSIX.1c -->
	<div class="defun">
	— Function: int <b>getpwnam_r</b> (<var>const char name, struct passwd result_buf, char buffer, size_t buflen, struct passwd *result</var>)<var><a name="index-getpwnam_005fr-3398"></a></var><br>
	<blockquote><p>This function is similar to <code>getpwnam</code> in that is returns
	information about the user whose user name is <var>name</var>. However, like
	<code>getpwuid_r</code>, it fills the user supplied buffers in
	<var>result_buf</var> and <var>buffer</var> with the information instead of using
	a static buffer.

	<p>The return values are the same as for <code>getpwuid_r</code>.
	</p></blockquote></div>

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