|USLEEP(3)||Linux Programmer's Manual||USLEEP(3)|
int usleep(useconds_t usec);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
- Since glibc 2.12:
(_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200809L) || /* Glibc since 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE
Before glibc 2.12:
- _BSD_SOURCE || _XOPEN_SOURCE >= 500
- Interrupted by a signal; see signal(7).
- usec is greater than or equal to 1000000. (On systems where that is considered an error.)
|usleep ()||Thread safety||MT-Safe|
On the original BSD implementation, and in glibc before version 2.2.2, the return type of this function is void. The POSIX version returns int, and this is also the prototype used since glibc 2.2.2.
Only the EINVAL error return is documented by SUSv2 and POSIX.1-2001.
#include <unistd.h> ... unsigned int usecs; ... usleep(usecs);
The interaction of this function with the SIGALRM signal, and with other timer functions such as 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) is unspecified.