#include <unistd.h> unsigned int sleep(unsigned int seconds);
sleep() causes the calling thread to sleep either until the number of real-time seconds specified in seconds have elapsed or until a signal arrives which is not ignored.
Zero if the requested time has elapsed, or the number of seconds left to sleep, if the call was interrupted by a signal handler.
For an explanation of the terms used in this section, see attributes(7).
|sleep()||Thread safety||MT-Unsafe sig:SIGCHLD/linux|
On Linux, sleep() is implemented via nanosleep(2). See the nanosleep(2) man page for a discussion of the clock used.
On some systems, sleep() may be implemented using alarm(2) and SIGALRM (POSIX.1 permits this); mixing calls to alarm(2) and sleep() is a bad idea.
Using longjmp(3) from a signal handler or modifying the handling of SIGALRM while sleeping will cause undefined results.
sleep(1), alarm(2), nanosleep(2), signal(2), signal(7)
This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
aio(7), alarm(2), clock_nanosleep(2), dskutil(1), getitimer(2), libperf-sampling(7), nanosleep(2), pthsem(3), signal(7), signal-safety(7), sleep(1), stress-ng(1), time(7), ualarm(3), upslog(8), usleep(3).