//bench/incr_pmutex5.c
#include	"unpipc.h"

#define	MAXNPROC	100

int		nloop;

struct shared {
  pthread_mutex_t	mutex;
  long	counter;
} *shared;		/* ,      */

void	*incr(void *);

int
main(int argc, char **argv)
{
	int		i, nprocs;
	pid_t	childpid[MAXNPROC];
	pthread_mutexattr_t	mattr;

	if (argc != 3)
		err_quit("usage: incr_pxmutex5 <#loops> <#processes>");
	nloop = atoi(argv[1]);
	nprocs = min(atoi(argv[2]), MAXNPROC);

		/*         */
	shared = My_shm(sizeof(struct shared));

		/*       */
	Pthread_mutexattr_init(&mattr);
	Pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
	Pthread_mutex_init(&shared->mutex, &mattr);
	Pthread_mutexattr_destroy(&mattr);
	Pthread_mutex_lock(&shared->mutex);

		/*    */
	for (i = 0; i < nprocs; i++) {
		if ( (childpid[i] = Fork()) == 0) {
			incr(NULL);
			exit(0);
		}
	}
		/*  :       */
	Start_time();
	Pthread_mutex_unlock(&shared->mutex);

		/*      */
	for (i = 0; i < nprocs; i++) {
		Waitpid(childpid[i], NULL, 0);
	}
	printf("microseconds: %.0f usec\n", Stop_time());
	if (shared->counter != nloop * nprocs)
		printf("error: counter = %ld\n", shared->counter);

	exit(0);
}
