SETREUID(2) System Calls SETREUID(2)
setreuid - set real and effective user ID
int setreuid (uid_t ruid, uid_t euid);
The real and effective user IDs of the current process are set accord-
ing 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 effective user ID and vice-versa; only the super-user may make
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.
Upon successful completion, a value of 0 is returned. Otherwise, a
value of -1 is returned and errno is set to indicate the error.
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.
getuid(2), seteuid(2), setuid(2)
The setreuid system call appeared in 4.2BSD.
GNO 16 January 1996 SETREUID(2)
Man(1) output converted with