SETREUID(3)               OpenBSD Programmer's Manual              SETREUID(3)

NAME
     setreuid - set real and effective user IDs



SYNOPSIS
     #include <unistd.h>

     int
     setreuid(int ruid, int euid);

DESCRIPTION
     The real and effective user IDs of the current process are set according
     to the arguments.  If ruid or euid is -1, the current UID is filled in by
     the system.  Unprivileged users may change the real user ID to the effec-
     tive 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 stan-
     dard setuid() function is preferred.

RETURN VALUES
     Upon successful completion, a value of 0 is returned.  Otherwise, a value
     of -1 is returned and errno is set to indicate the error.

ERRORS
     [EPERM]       The current process is not the super-user and a change oth-
                   er 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.

OpenBSD 2.6                     March 10, 1991                               1