Name
sleep - sleep for a specified number of secondsLibrary
Standard C library ( libc ", " -lc )Synopsis
#include <unistd.h> unsigned int sleep(unsigned int " "seconds );
Description
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.Return Value
Zero if the requested time has elapsed, or the number of seconds left to sleep, if the call was interrupted by a signal handler.Attributes
For an explanation of the terms used in this section, see attributes(7).| Interface | Attribute | Value |
| T} | Thread safety | MT-Unsafe sig:SIGCHLD/linux |
Versions
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.