getresuid, getresgid − get real, effective and saved user or group ID

#define _GNU_SOURCE
#include <unistd.h>

int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);

getresuid and getresgid (both introduced in Linux 2.1.44) get the real, effective and saved user ID’s (resp. group ID’s) of the current process.

On success, zero is returned. On error, −1 is returned, and errno is set appropriately.

EFAULT

One of the arguments specified an address outside the calling program’s address space.

This call is Linux-specific. The prototype is given by glibc since version 2.3.2 provided _GNU_SOURCE is defined.

getuid(2), setuid(2), setreuid(2), setresuid(2)