4.3BSD - /usr/man/cat3/setuid.0

SETUID(3)                                                            SETUID(3)


NAME
       setuid, seteuid, setruid, setgid, setegid, setrgid - set user and group
       ID

SYNOPSIS
       #include <sys/types.h>

       setuid(uid)
       seteuid(euid)
       setruid(ruid)
       uid_t uid, euid, ruid;

       setgid(gid)
       setegid(egid)
       setrgid(rgid)
       gid_t gid, egid, rgid;

DESCRIPTION
       Setuid (setgid) sets both the real and effective user ID (group ID)  of
       the current process to as specified.

       Seteuid  (setegid) sets the effective user ID (group ID) of the current
       process.

       Setruid (setrgid) sets the real user ID (group ID) of the current  pro‐
       cess.

       These  calls are only permitted to the super-user or if the argument is
       the real or effective ID.

SEE ALSO
       setreuid(2), setregid(2), getuid(2), getgid(2)

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


4.2 Berkeley Distribution        May 12, 1986                        SETUID(3)