intro(2) System Calls Manual intro(2) intro - 2 . . : C ( ) . . C : o o (trap) o errno . . 2 API C ( GNU) . (DESCRIPTION) C (NOTES). syscalls(2). ( errno(3)). C : errno -1 . . 0 . . (SYNOPSIS) . ( ). . feature_test_macros(7). UNIX . standards(7). C . syscall(2). _syscall _syscall(2). () . ! _syscall(2), syscall(2), syscalls(2), errno(3), intro(3), capabilities(7), credentials(7), feature_test_macros(7), mq_overview(7), path_resolution(7), pipe(7), pty(7), sem_overview(7), shm_overview(7), signal(7), socket(7), standards(7), symlink(7), system_data_types(7), sysvipc(7), time(7) 3 . . : . 6.18 8 2026 intro(2)