NAME

getresuid, getresgid - get real, effective, and saved user/group IDs

LIBRARY

Standard C library (libc, -lc)

SYNOPSIS

#define _GNU_SOURCE         /* See feature_test_macros(7) */
#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);

DESCRIPTION

getresuid() returns the real UID, the effective UID, and the saved set-user-ID of the calling process, in the arguments ruid, euid, and suid, respectively. getresgid() performs the analogous task for the process's group IDs.

RETURN VALUE

On success, zero is returned. On error, -1 is returned, and errno is set to indicate the error.

ERRORS

EFAULT: One of the arguments specified an address outside the calling program's address space.

VERSIONS

These system calls were added on Linux 2.1.44.

The prototypes are given since glibc 2.3.2, provided _GNU_SOURCE is defined.

STANDARDS

These calls are nonstandard; they also appear on HP-UX and some of the BSDs.

NOTES

The original Linux getresuid() and getresgid() system calls supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added getresuid32() and getresgid32(), supporting 32-bit IDs. The glibc getresuid() and getresgid() wrapper functions transparently deal with the variations across kernel versions.