setresuid, setresgid - set real, effective and saved user or
int setresuid(uid_t ruid, uid_t euid, uid_t suid
int setresgid(gid_t rgid, gid_t egid, gid_t sgid
setresuid (introduced in Linux 2.1.44) sets the real, effec-
tive and saved user ID's of the current process.
Unprivileged user processes (i.e., processes with each of
real, effective and saved user ID nonzero) may change the
real, effective and saved user ID, each to one of: the
current uid, the current effective uid or the current saved
The super-user may set real, effective and saved user ID to
If one of the parameters equals -1, the corresponding value
is not changed.
Completely analogously, setresgid sets the real, effective
and saved group ID's of the current process, with the same
restrictions for processes with each of real, effective and
saved user ID nonzero.
On success, zero is returned. On error, -1 is returned, and
errno is set appropriately.
The current process was not privileged and tried to
change the IDs is a not allowed way.
This call is Linux-specific.
getuid(2), setuid(2), getreuid(2), setreuid(2), getresuid(2)