/*process-1.c*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <semaphore.h>

int main(int argc, char *argv[]) {
   	sem_t *mutex;
   	char *c = "This is CSCI3150--An operating system course.\n";
	// specify no buffering for stderr
	setbuf(stderr, NULL); 
   	mutex = sem_open("mutex_for_stderr", O_CREAT, 0666, 1);
  	 sem_wait(mutex);
   	while (*c != '\0') {
        	fputc(*c, stderr); 
        	c++;
        	sleep(1);
    	 }
	sem_post(mutex);
	sem_close(mutex);
	sem_unlink("mutex_for_stderr");
	return 0;
}