daemon(3) Library Functions Manual daemon(3) daemon - (libc -lc) #include int daemon(int nochdir, int noclose); glibc ( feature_test_macros(7)): daemon(): glibc 2.21: _DEFAULT_SOURCE glibc 2.19 2.20: _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) glibc 2.19 : _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) daemon() . nochdir daemon() ("/") . noclose daemon() /dev/null . ( fork(2) _exit(2) .) daemon() . daemon() -1 errno fork(2) setsid(2). attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |daemon() | | MT-Safe | +------------+------------------------------------+--------------------+ BSD. glibc -1 /dev/null . errno. . 4.4BSD. GNU C BSD ( fork(2) setsid(2) fork(2)) . . System V ( Linux) . fork(2), setsid(2), daemon(7), logrotate(8) 3 . . : . 6.18 17 2025 daemon(3)