Portable semaphores

Linux and macOS natively supports different types of semaphores. In order to have a single (simple) semaphore API that works on both Linux and macOS you will use a portable semaphore library named psem.

In the module-4/mandatory/psem/psem.h header file you find the documentation of the portable semaphore API.

Example usage

A small example program that demonstrates how to use the sempaphores provided by the psem library.


#include "psem.h"

int main(void) {
  // Create a new semaphore and initialize the semaphore counter to 3. 
  psem_t *sem = psem_init(3);

  // Wait on the semaphore. 
  psem_wait(sem);

  // Signal on the semaphore. 
  psem_signal(sem);

  // Destroy the semaphore (deallocation)
  psem_destroy(sem)
}

Example program

In module-4/mandatory/src/psem_test.c you find a complete example program with two threads (main and a pthread) that synchronize their execution using a psem semaphore.

Compile

In the terminal, navigate to the module-4/mandatory directory. Use make to compile the program.

$ make

Run

Run the program from the terminal.

$ ./bin/psem_test