NAME
setreuid - set real and effective user ID’s

SYNOPSIS
setreuid(ruid, euid)
int ruid, euid;

DESCRIPTION
The real and effective user ID’s 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 effective user ID and vice-versa; only the super-
user may make other changes.

RETURN VALUE
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 other than changing the effective user-id to
the real user-id was specified.

SEE ALSO
getuid(2), setregid(2), setuid(3)