v7 man page for setuid

SETUID(2)							System Calls Manual							 SETUID(2)

NAME
       setuid, setgid - set user and group ID

SYNOPSIS
       setuid(uid)

       setgid(gid)

DESCRIPTION
       The  user  ID  (group ID) of the current process is set to the argument.  Both the effective and the real ID are set.  These calls are only
       permitted to the super-user or if the argument is the real ID.

SEE ALSO
       getuid(2)

DIAGNOSTICS
       Zero is returned if the user (group) ID is set; -1 is returned otherwise.

ASSEMBLER
       (setuid = 23.)
       (user ID in r0)
       sys setuid

       (setgid = 46.)
       (group ID in r0)
       sys setgid

																	 SETUID(2)