SETREGID(2) BSD Programmer's Manual SETREGID(2)NAMEsetregid - set real and effective group IDs
SYNOPSIS
#include <unistd.h>
int
setregid(gid_t rgid, gid_t egid);
DESCRIPTION
The real and effective group IDs of the current process are set according
to the arguments. If the real group ID is changed, the saved group ID is
changed to the new value of the effective group ID.
Unprivileged users may change either group ID to the current value of the
real, effective, or saved group ID. Only the superuser may make other
changes.
Supplying a value of -1 for either the real or effective group ID forces
the system to substitute the current ID in place of the -1 parameter.
The setregid() function was intended to allow swapping the real and ef-
fective group IDs in set-group-ID programs to temporarily relinquish the
set-group-ID value. This purpose is now better served by the use of the
setegid() function (see setuid(2)).
When setting the real and effective group IDs to the same value, the set-
gid() function is preferred.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value
of -1 is returned and errno is set to indicate the error.
ERRORS
[EPERM] The current process is not the superuser and a change other
than changing the effective group ID to the real group ID
was specified.
SEE ALSOgetgid(2), setegid(2), setgid(2), setresgid(2), setuid(2)STANDARDS
The setregid() function conforms to the IEEE Std 1003.1-2001 ("POSIX")
and X/Open Portability Guide Issue 4.3 ("XPG4.3"). specifications.
Note, however, that prior to IEEE Std 1003.1-2001 ("POSIX"), the setre-
gid() function was not a part of the IEEE Std 1003.1 ("POSIX") specifica-
tion. As a result, it may not be implemented on all systems.
HISTORY
The setregid() function call appeared in 4.2BSD. A semantically different
version appeared in 4.4BSD. The current version, with the original seman-
tics restored, appeared in OpenBSD 3.3.
CAVEATS
The setregid() function predates POSIX saved group IDs. This implementa-
tion changes the saved group ID to the new value of the effective group
ID if the real group ID is changed. Other implementations may behave dif-
ferently.
MirOS BSD #10-current January 29, 2003 1
