setgid (2)

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 current 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 re-engage 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 effective 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) Linux 2002-03-09 SETGID(2)