plan9 man page for setgid

SETGID(3P)						     POSIX Programmer's Manual							SETGID(3P)

PROLOG
       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME
       setgid - set-group-ID

SYNOPSIS
       #include <unistd.h>

       int setgid(gid_t gid);

DESCRIPTION
       If the process has appropriate privileges, setgid() shall set the real group ID, effective group ID, and  the  saved  set-group-ID  of  the
       calling process to gid.

       If  the	process  does not have appropriate privileges, but gid is equal to the real group ID or the saved set-group-ID, setgid() shall set
       the effective group ID to gid; the real group ID and saved set-group-ID shall remain unchanged.

       The setgid() function shall not affect the supplementary group list in any way.

       Any supplementary group IDs of the calling process shall remain unchanged.

RETURN VALUE
       Upon successful completion, 0 is returned. Otherwise, -1 shall be returned and errno set to indicate the error.

ERRORS
       The setgid() function shall fail if:

       EINVAL The value of the gid argument is invalid and is not supported by the implementation.

       EPERM  The process does not have appropriate privileges and gid does not match the real group ID or the saved set-group-ID.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       Refer to the RATIONALE section in setuid().

FUTURE DIRECTIONS
       None.

SEE ALSO
       exec(), getegid(), geteuid(), getgid(), getuid(), setegid(), seteuid(), setregid(), setreuid(), setuid(), the Base  Definitions	volume	of
       IEEE Std 1003.1-2001, <sys/types.h>, <unistd.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 .

IEEE
/The Open Group						       2003								SETGID(3P)