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Linux系统调用

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<TITLE>Syscall specifications of Linux - setuid</TITLE>
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<H2><A NAME="SEC69" HREF="syscalls_toc.html#SEC69" tppabs="http://personal.xfol.com/%7erezaie/syscall/syscalls_toc.html#SEC69">setuid</A></H2>
<P>
<H3>SYNOPSIS</H3>
<P>
<CODE>int setuid(gid_t <VAR>uid</VAR>);</CODE>
<P>
<H3>PARAMETERS</H3>
<P>
<VAR>uid</VAR>: [in] the new uid.
<P>
<H3>DESCRIPTION</H3>
<P>
If the calling task does not have superuser privileges, it may use
<CODE>setuid</CODE> to sets its effective uid to its saved uid or its real uid
(other values are illegal). If the calling task has superuser
privileges, the real, effective and saved uids are set to <VAR>uid</VAR>.
<P>
<H3>RETURN VALUE</H3>
<P>
On success, returns 0. On error, returns -1 and <CODE>errno</CODE> is set
to one of the following values: <CODE>EPERM</CODE>: the <VAR>uid</VAR> is not the
real uid or the saved uid of the task and the task does not have
superuser privileges.
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