redhat man page for getresgid

GETRESUID(2)						     Linux Programmer's Manual						      GETRESUID(2)

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

SYNOPSIS
       #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  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.

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

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

CONFORMING TO
       This call is Linux-specific.

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

Linux 2.1.44							    1997-07-16							      GETRESUID(2)