opensolaris man page for setregid

setregid(2)							   System Calls 						       setregid(2)

NAME
       setregid - set real and effective group IDs

SYNOPSIS
       #include <unistd.h>

       int setregid(gid_t rgid, gid_t egid);

DESCRIPTION
       The  setregid()	function  is used to set the real and effective group IDs of the calling process.  If rgid is -1, the real group ID is not
       changed; if egid is -1, the effective group ID is not changed.  The real and effective group IDs may be set to different values in the same
       call.

       If  the	{PRIV_PROC_SETID}  privilege is asserted in the effective set of the calling process, the real group ID and the effective group ID
       can be set to any legal value.

       If the {PRIV_PROC_SETID} privilege is not asserted in the effective set of the calling process, either the real group ID can be set to  the
       saved set-group-ID from execve(2), or the effective group ID can either be set to the saved set-group-ID or the real group ID.

       In  either  case, if the real group ID is being changed (that is, if rgid is not -1), or the effective group ID is being changed to a value
       not equal to the real group ID, the saved set-group-ID is set equal to the new effective group ID.

RETURN VALUES
       Upon successful completion, 0 is returned. Otherwise, -1 is returned, errno is set to indicate the error, and neither of the group IDs will
       be changed.

ERRORS
       The setregid() function will fail if:

       EINVAL	 The value of rgid or egid is less than 0 or greater than UID_MAX (defined in <limits.h>).

       EPERM	 The  {PRIV_PROC_SETID}  privilege  is not asserted in the effective set of the calling processes and a change was specified other
		 than changing the real group ID to the saved set-group-ID or changing the effective group ID to the real group ID  or	the  saved
		 group ID.

USAGE
       If  a set-group-ID process sets its effective group ID to its real group ID, it can still set its effective group ID back to the saved set-
       group-ID.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       execve(2), getgid(2), setreuid(2), setuid(2), attributes(5), privileges(5), standards(5)

SunOS 5.11							    22 Mar 2004 						       setregid(2)