/* pthreadex.c */

/* This version is used to test Peterson's algorithm for N threads */

/* To compile (on a Solaris == SunOS 5.x machine )        */
/*    cc pthreadex.c -lpthread -lrt                       */
/* To run                                                 */
/*    a.out 1000000                                       */

#include <stdio.h>
#include <pthread.h>
#include <sched.h>

#define MAX_THREADS 16         /* Maximum possible number of threads  */
#define NUM_THREADS  2         /* Number of threads to us in this run */

pthread_t td[MAX_THREADS];      /* Thread descriptors for the new threads */
pthread_attr_t attr;
pthread_mutex_t t_mtx  = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t  t_cond = PTHREAD_COND_INITIALIZER;

volatile int shared = 0;       /* The shared variable being updated */
int loopcount = 100000;        /* Default value for increment count */
int lastid = 0;

void pete_lock(int tid);
void pete_unlock(int tid);

/* We will run instances of this function as separate threads */

void xthread(
int  id)       /* Logical thread id.. values are 0, 1, 2,... */
{
   int i;
   int local;
/* sleep(1);   */
   printf("Made it in %d \n", id);

   for (i = 0; i < loopcount; i++)
   {
      pete_lock(id);
      local = shared;
      local += 1;
      shared = local;
      pete_unlock(id);
   }
   pthread_exit((void *)0);
}

int  main(
int argc,
char **argv)
{
   int tid;
   int pri;
   int stat;
   int tstatus;

/* Override loop count if user supplied one */

   if (argc > 1)
      sscanf(argv[1], "%d", &loopcount);

   pthread_attr_init(&attr);
   pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);

/* Create the threads */

   for (tid = 0; tid < NUM_THREADS; tid++)
   {
      pthread_create(&td[tid], &attr, (void *)xthread, (void *)tid);
   }

/* Wait for all  to terminate */

   for (tid = 0; tid < NUM_THREADS; tid++)
   {
      stat = pthread_join(td[tid], NULL);
      printf("Thread %d done \n", tid);
   }

   printf("Made it out \n");
   printf("Value of shared is %d \n",  shared);
   return(0);
}