sleep()

Suspend a thread for a given length of time

Synopsis:

#include <unistd.h>

unsigned int sleep( unsigned int seconds );

Arguments:

seconds
The number of realtime seconds that you want to suspend the thread for.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The sleep() function suspends the calling thread until the number of realtime seconds specified by the seconds argument have elapsed, or the thread receives a signal whose action is either to terminate the process or to call a signal handler. The suspension time may be greater than the requested amount, due to the nature of time measurement (see the Tick, Tock: Understanding the Neutrino Microkernel's Concept of Time chapter of the QNX Neutrino Programmer's Guide), or due to the scheduling of other, higher priority threads by the system.

Returns:

0 if the full time specified was completed; otherwise, the number of seconds unslept if interrupted by a signal.

Examples:

/*
 * The following program sleeps for the
 * number of seconds specified in argv[1].
 */
#include <stdlib.h>
#include <unistd.h>

int main( int argc, char **argv )
{
    unsigned seconds;

    seconds = (unsigned) strtol( argv[1], NULL, 0 );
    sleep( seconds );
    
    return EXIT_SUCCESS;
}

Classification:

POSIX 1003.1

Safety:
Cancellation point Yes
Interrupt handler No
Signal handler Yes
Thread Yes