.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "SETGID" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" setgid 
.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
setgid \- set-group-ID
.SH SYNOPSIS
.LP
\fB#include <unistd.h>
.br
.sp
int setgid(gid_t\fP \fIgid\fP\fB);
.br
\fP
.SH DESCRIPTION
.LP
If the process has appropriate privileges, \fIsetgid\fP() shall set
the real group ID, effective group ID, and the saved
set-group-ID of the calling process to \fIgid\fP.
.LP
If the process does not have appropriate privileges, but \fIgid\fP
is equal to the real group ID or the saved set-group-ID,
\fIsetgid\fP() shall set the effective group ID to \fIgid\fP; the
real group ID and saved set-group-ID shall remain
unchanged.
.LP
The \fIsetgid\fP() function shall not affect the supplementary group
list in any way.
.LP
Any supplementary group IDs of the calling process shall remain unchanged.
.SH RETURN VALUE
.LP
Upon successful completion, 0 is returned. Otherwise, -1 shall be
returned and \fIerrno\fP set to indicate the error.
.SH ERRORS
.LP
The \fIsetgid\fP() function shall fail if:
.TP 7
.B EINVAL
The value of the \fIgid\fP argument is invalid and is not supported
by the implementation.
.TP 7
.B EPERM
The process does not have appropriate privileges and \fIgid\fP does
not match the real group ID or the saved
set-group-ID.
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
None.
.SH RATIONALE
.LP
Refer to the RATIONALE section in \fIsetuid\fP().
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIexec\fP(), \fIgetegid\fP(), \fIgeteuid\fP(), \fIgetgid\fP(),
\fIgetuid\fP(),
\fIsetegid\fP(), \fIseteuid\fP(), \fIsetregid\fP(), \fIsetreuid\fP(),
\fIsetuid\fP(),
the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<sys/types.h>\fP,
\fI<unistd.h>\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html .