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.TH SETEUID "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.

.SH NAME
seteuid
\(em set effective user ID
.SH SYNOPSIS
.LP
.nf
#include <unistd.h>
.P
int seteuid(uid_t \fIuid\fP);
.fi
.SH DESCRIPTION
If
.IR uid
is equal to the real user ID or the saved set-user-ID, or if the
process has appropriate privileges,
\fIseteuid\fR()
shall set the effective user ID of the calling process to
.IR uid ;
the real user ID and saved set-user-ID shall remain unchanged.
.P
The
\fIseteuid\fR()
function shall not affect the supplementary group list in any way.
.SH "RETURN VALUE"
Upon successful completion, 0 shall be returned; otherwise, \(mi1 shall
be returned and
.IR errno
set to indicate the error.
.SH ERRORS
The
\fIseteuid\fR()
function shall fail if:
.TP
.BR EINVAL
The value of the
.IR uid
argument is invalid and is not supported by the implementation.
.TP
.BR EPERM
The process does not have appropriate privileges and
.IR uid
does not match the real user ID or the saved set-user-ID.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
Refer to the RATIONALE section in
.IR "\fIsetuid\fR\^(\|)".
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIexec\fR\^",
.IR "\fIgetegid\fR\^(\|)",
.IR "\fIgeteuid\fR\^(\|)",
.IR "\fIgetgid\fR\^(\|)",
.IR "\fIgetuid\fR\^(\|)",
.IR "\fIsetegid\fR\^(\|)",
.IR "\fIsetgid\fR\^(\|)",
.IR "\fIsetregid\fR\^(\|)",
.IR "\fIsetreuid\fR\^(\|)",
.IR "\fIsetuid\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2008,
.IR "\fB<sys_types.h>\fP",
.IR "\fB<unistd.h>\fP"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .

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