getuid(2) System Calls Manual getuid(2) getuid, geteuid - C (libc, -lc) #include uid_t getuid(void); uid_t geteuid(void); getuid() (ID) . geteuid() . errno. POSIX.1-2024. 4.3BSD, POSIX.1-1988. UNIX V6 getuid() (euid << 8) + uid. UNIX V7 getuid() geteuid(). getuid() geteuid() Linux 16- . Linux 2.4 getuid32() geteuid32(), 32- . glibc getuid() geteuid() . Alpha getuid() geteuid() getxuid(), UID. glibc getuid() geteuid() . syscall(2). getresuid(2), setreuid(2), setuid(2), credentials(7) () Azamat Hackimov , Dmitry Bolkhovskikh , Vladislav , Yuri Kozlov ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () <>. Linux 6.17 8 2026 . getuid(2)