I have some source code that was compiled on Windows. I am converting it to run on Red Hat Linux.
The source code has included the <windows.h>
header file and the programmer has used the Sleep()
function to wait for a period of milliseconds. This won't work on the Linux.
However, I can use the sleep(seconds)
function, but that uses integer in seconds. I don't want to convert milliseconds to seconds. Is there a alternative sleep function that I can use with gcc compiling on Linux?
#include <stdio.h>
#include <stdlib.h>
int main () {
puts("Program Will Sleep For 2 Seconds");
system("sleep 2"); // works for linux systems
return 0;
}
Alternatively to usleep()
, which is not defined in POSIX 2008 (though it was defined up to POSIX 2004, and it is evidently available on Linux and other platforms with a history of POSIX compliance), the POSIX 2008 standard defines nanosleep()
:
nanosleep
- high resolution sleep#include <time.h> int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
The
nanosleep()
function shall cause the current thread to be suspended from execution until either the time interval specified by therqtp
argument has elapsed or a signal is delivered to the calling thread, and its action is to invoke a signal-catching function or to terminate the process. The suspension time may be longer than requested because the argument value is rounded up to an integer multiple of the sleep resolution or because of the scheduling of other activity by the system. But, except for the case of being interrupted by a signal, the suspension time shall not be less than the time specified byrqtp
, as measured by the system clock CLOCK_REALTIME.The use of the
nanosleep()
function has no effect on the action or blockage of any signal.
Beyond usleep, the humble select with NULL file descriptor sets will let you pause with microsecond precision, and without the risk of SIGALRM
complications.
sigtimedwait and sigwaitinfo offer similar behavior.
You can use this cross-platform function:
#ifdef WIN32
#include <windows.h>
#elif _POSIX_C_SOURCE >= 199309L
#include <time.h> // for nanosleep
#else
#include <unistd.h> // for usleep
#endif
void sleep_ms(int milliseconds){ // cross-platform sleep function
#ifdef WIN32
Sleep(milliseconds);
#elif _POSIX_C_SOURCE >= 199309L
struct timespec ts;
ts.tv_sec = milliseconds / 1000;
ts.tv_nsec = (milliseconds % 1000) * 1000000;
nanosleep(&ts, NULL);
#else
if (milliseconds >= 1000)
sleep(milliseconds / 1000);
usleep((milliseconds % 1000) * 1000);
#endif
}
#include <unistd.h>
int usleep(useconds_t useconds); //pass in microseconds
Source: Stackoverflow.com