SETGID(2)		   Linux Programmers Manual		    SETGID(2)



NAME
       setgid - set group identity

SYNOPSIS
       #include 
       #include 

       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 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)

COLOPHON
       This page is part of release 3.05 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				  2002-03-09			     SETGID(2)