What is the proper #include for the function 'sleep()'?

Question

I am using the Big Nerd Ranch book Objective-C Programming, and it starts out by having us write in C in the first few chapters. In one of my programs it has me create, I us

Answer 1

The sleep man page says it is declared in <unistd.h>.

Synopsis:

#include <unistd.h>

unsigned int sleep(unsigned int seconds);

Answer 2

What is the proper #include for the function 'sleep()'?

sleep() isn't Standard C, but POSIX so it should be:

#include <unistd.h>

Answer 3

this is what I use for a cross-platform code:

#ifdef _WIN32
#include <Windows.h>
#else
#include <unistd.h>
#endif

int main()
{
  pollingDelay = 100
  //do stuff

  //sleep:
  #ifdef _WIN32
  Sleep(pollingDelay);
  #else
  usleep(pollingDelay*1000);  /* sleep for 100 milliSeconds */
  #endif

  //do stuff again
  return 0;
}

Answer 4

sleep is a non-standard function.

• On UNIX, you shall include <unistd.h>.
• On MS-Windows, Sleep is rather from <windows.h>.

In every case, check the documentation.

Answer 5

sleep(3) is in unistd.h, not stdlib.h. Type man 3 sleep on your command line to confirm for your machine, but I presume you're on a Mac since you're learning Objective-C, and on a Mac, you need unistd.h.