getgid(2) System Calls Manual getgid(2)

getgid, getegid - get group identity

Standard C library (libc, -lc)

#include <unistd.h>
gid_t getgid(void);
gid_t getegid(void);

getgid() returns the real group ID of the calling process.

getegid() returns the effective group ID of the calling process.

These functions are always successful and never modify errno.

On Alpha, instead of a pair of getgid() and getegid() system calls, a single getxgid() system call is provided, which returns a pair of real and effective GIDs. The glibc getgid() and getegid() wrapper functions transparently deal with this. See syscall(2) for details regarding register mapping.

POSIX.1-2008.

POSIX.1-2001, 4.3BSD.

The original Linux getgid() and getegid() system calls supported only 16-bit group IDs. Subsequently, Linux 2.4 added getgid32() and getegid32(), supporting 32-bit IDs. The glibc getgid() and getegid() wrapper functions transparently deal with the variations across kernel versions.

getresgid(2), setgid(2), setregid(2), credentials(7)

2023-10-31 Linux man-pages 6.06