usleep(3) Library Functions Manual usleep(3) usleep - (libc -lc) #include int usleep(useconds_t usec); glibc ( feature_test_macros(7)): usleep(): glibc 2.12: (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200809L) || /* glibc >= 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE glibc 2.12: _BSD_SOURCE || _XOPEN_SOURCE >= 500 usleep() ( ) usec . . usleep() 0 . -1 errno . EINTR signal(7). EINVAL usec 1000000. ( .) attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |usleep() | | MT-Safe | +------------+------------------------------------+--------------------+ . 4.3BSD, POSIX.1-2001. POSIX.1-2001 nanosleep(2) . POSIX.1-2008. BSD glibc 2.2.2 void. POSIX int glibc 2.2.2. EINVAL SUSv2 POSIX.1-2001. SIGALRM alarm(2), sleep(3), nanosleep(2), setitimer(2), timer_create(2), timer_delete(2), timer_getoverrun(2), timer_gettime(2), timer_settime(2), ualarm(3) . alarm(2), getitimer(2), nanosleep(2), select(2), setitimer(2), sleep(3), ualarm(3), useconds_t(3type), time(7) 3 . . : . 6.18 8 2026 usleep(3)