SETGID(2) Linux Programmer's Manual SETGID(2)
NAME
setgid - set group identity
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int setgid(gid_t gid);
DESCRIPTION
setgid() sets the effective group ID of the calling process. If the caller is the superuser, the real GID and saved set-group-ID are also
set.
Under Linux, setgid() is implemented like the POSIX version with the _POSIX_SAVED_IDS feature. This allows a set-group-ID program that is
not set-user-ID-root to drop all of its group privileges, do some un-privileged work, and then reengage the original effective group ID in
a secure manner.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
ERRORS
EPERM The calling process is not privileged (does not have the CAP_SETGID capability), and gid does not match the real group ID or saved
set-group-ID of the calling process.
CONFORMING TO
SVr4, POSIX.1-2001.
SEE ALSO
getgid(2), setegid(2), setregid(2), capabilities(7), credentials(7)
COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2009-10-17 SETGID(2)
