getresuid(2)                                            System Calls Manual                                            getresuid(2)

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.

SEE ALSO
       getuid(2), setresuid(2), setreuid(2), setuid(2), credentials(7)

Linux man-pages 6.03                                         2022-12-04                                                getresuid(2)