ejercicio6.c

#include <stdio.h>
#include <omp.h>

#define MAXWORK 40

int work[MAXWORK],
    nwork=0,  
    nextput=0,
    nextget=-1, 
    breaksum,
    done = 0,
    psum,csum,
    pwork,
    *cwork,
    nth,


void next(int *m)
{  (*m)++; 
   if (*m >= MAXWORK) *m = 0;
}

void putwork(int k)
{  int put = 0;
   while (!put)  {  
      if (nwork < MAXWORK)  {
         #pragma omp critical
         {  work[nextput] = k;
            if (nwork == 0) nextget = nextput;
            next(&nextput);
            nwork++;
            put = 1;
         }
      }
      else sched_yield();
   }
}

int getwork()
{  int k,get=0;
   while (!get)  {
      if (done && nwork == 0) return -1;
         #pragma omp critical
         {
            if (nwork > 0)  {
               k = work[nextget];
               next(&nextget);
               nwork--;
               if (nwork == 0) nextget = -1;
               get = 1;
            }
         }
      
   }
   return k;
}

void dowork()
{  
   #pragma omp parallel  
   {  int me = omp_get_thread_num(),
          num;
      #pragma omp single
      {  int i;
         nth = omp_get_num_threads();  
         printf("there are %d threads\n",nth);
         cwork = (int *) malloc(nth*sizeof(int));
         for (i = 1; i < nth; i++) cwork[i]=0;
      }

      #pragma omp barrier  
      if (me == 0)  {
         pwork = 0;
         while (1)  {
            num = rand() % 100;
            putwork(num);
            psum += num;
            pwork++;
            if (psum > breaksum)  {
               done = 1;
               break;
            }
         }
      }
      else  {
         while (1)  {
            num = getwork();
            if (num == -1) break;
            cwork[me]++;
            #pragma omp atomic
            csum += num;
         }
      }
   }
}

int main(int argc, char **argv)
{  int i;
   breaksum = atoi(argv[1]);
   dowork();
   printf("sum by producer:  %d\n",psum);
   printf("sum by consumers:  %d\n",csum);
   printf("work by producer:  %d\n",pwork);
   printf("work by consumers:\n");
   for (i = 1; i < nth; i++) 
      printf("%d\n",cwork[i]);
}