sleep3
Sleep for a specified number of seconds
Usage
#include <unistd.h>
unsigned int sleep(unsigned int seconds);
Library
Standard C library (libc, -lc)
Overview
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 |
| sleep() | 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.
Caveats
Using longjmp(3) from a signal handler or modifying the handling of SIGALRM while sleeping will cause undefined results.
Releases
19 releases since Debian 1.1 (Buzz); the text changed 13 times.