setgid

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 and saved group ID’s are also set.

       Under Linux, setgid is implemented like the  POSIX  version  with  the
       _POSIX_SAVED_IDS	 feature.   This  allows a setgid program that is not
       suid 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  user	 is  not the super-user (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, SVID.

SEE ALSO
       getgid(2), setregid(2), setegid(2)



Linux 2.5			  2002-03-09			    SETGID(2)