SETREUID(2)	    UNIX Programmer's Manual	      SETREUID(2)



NAME
     setreuid - set real and effective user ID's

SYNOPSIS
     #include <unistd.h>

     _i_n_t
     setreuid(ruid, euid)
	 uid_t ruid, euid

DESCRIPTION
     The real and effective user IDs of the current process are
     set according to the arguments.  If _r_u_i_d or _e_u_i_d is -1, the
     current uid is filled in by the system.  Unprivileged users
     may change the real user ID to the effective user ID and
     vice-versa; only the super-user may make other changes.

     The setreuid function has been used to swap the real and
     effective user IDs in set-user-ID programs to temporarily
     relinquish the set-user-ID value.	This purpose is now
     better served by the use of the seteuid function (see
     setuid(2)).

     When setting the real and effective user IDs to the same
     value, the standard setuid function is preferred.

RETURN VALUES
     Upon successful completion, a value of 0 is returned.  Oth-
     erwise, a value of -1 is returned and _e_r_r_n_o is set to indi-
     cate the error.

ERRORS
     EPERM     The current process is not the super-user and a
	       change other than changing the effective user-id
	       to the real user-id was specified.

SEE ALSO
     getuid(2), seteuid(2), setuid(2)

HISTORY
     The setreuid function call appeared in 4.2BSD and was
     dropped in 4.4BSD.













Printed 11/26/99	December 3, 1997			1