SETREGID(2)

NAME
setregid - set real and effective group ID

SYNOPSIS
#include <unistd.h>
int
setregid(gid_t rgid, gid_t egid);

DESCRIPTION
The real and effective group ID's of the current process are set to the arguments. Unprivileged users may change the real group ID to the effective group ID and vice-versa; only the super-user 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 effective group IDs in set-group-ID programs to temporarily relinquish the set-group-ID value. This function did not work correctly, and its 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 standard setgid() 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 super-user and a change other than changing the effective group-id to the real group-id was specified.

SEE ALSO
getgid(2), setegid(2), setgid(2), setuid(2)

HISTORY
The setregid system call appeared in 4.2BSD.