SETUID(3)                            BSD                             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
     process.

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

NOTES
     Under some implementations of the UNIX operating system, the setgid call
     will modify the supplementary group list.  This is not the case under
     Domain/OS.

     At login time, the user's native group is automatically added to the
     supplementary group list.  Therefore, a setgid call will leave the user
     in that original group (since the supplementary list is not changed).

     Note that on a native BSD system, the setgid system call purges old
     native group from the supplementary group list and adds the new group to
     it.

SEE ALSO
     intro(2), getgid(2), getoid(2), getuid(2), setregid(2), setreoid(2),
     setreuid(2), setoid(3).

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