how does sleep work internally?

meetbhattu · #1 (**permalink**) 10-29-2007

hi can someone explain how the sleep() function actually works, like where is it defined, wat files does it refer etc...?

porter · #2 (**permalink**) 10-29-2007

/bin/sleep (or /usr/bin/sleep) is a program that basically does

Code:

#include <stdlib.h>
#include <string.h>
int main(int argc,char **argv)
{
    sleep(atol(argv[1]));
    return 0;
}

The sleep() function puts the current execution context to sleep, it does this by calling a syscall to invoke the kernel sleep function which atomically
(a) sets a wake-up timer
(b) marks the current process as sleeping
(c) waits until the wakeup-timer fires or an interrupt occurs

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