int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid); int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);
returns the real UID, the effective UID, and the saved set-user-ID
of the calling process, in the arguments
performs the analogous task for the process's group IDs.
On success, zero is returned.
On error, -1 is returned, and
is set appropriately.
One of the arguments specified an address outside the calling program's
These system calls appeared on Linux starting with kernel 2.1.44.
The prototypes are given by glibc since version 2.3.2,
These calls are nonstandard;
they also appear on HP-UX and some of the BSDs.