SETREUID(2) BSD System Calls Manual SETREUID(2)NAMEsetreuid — set real and effective user ID's
setreuid(uid_t ruid, uid_t euid);
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.
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
SEE ALSOgetuid(2), seteuid(2), setuid(2)HISTORY
The setreuid function call appeared in 4.2BSD and was dropped in 4.4BSD.
4th Berkeley Distribution April 16, 1994 4th Berkeley Distribution