Thread: pthread with c

You need to learn how to indent code before going much further.

Clear and consistent indentation is key to understanding.

Code:

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


void *thread1(int N, long long int array[])
{
  while (1) {
    int i;
    long long int T1 = 0;
    for (i = 0; i < N; i++) {
      printf("array[%d]=%lld\n", i, array[i]);
      T1 = T1 + array[i];
    }
    printf("T1=%lld\n", T1);
  }
}


void *thread2(int N, long long int array[])
{
  while (1) {
    {
      int i;
      long long int T2 = 1;

      for (i = 0; i < N; i++) {
        T2 = T2 * array[i];
      }
      printf("T2=%lld\n", T2);
      return T2;
    }
  }
}


void *thread4(long long int P4array[])
{
  while (1) {
    int i, j;
    long long int temp = 0;

    for (i = 0; i < 2; i++) {
      for (j = i + 1; j < 3; j++) {
        if (P4array[j] > P4array[i]) {
          temp = P4array[i];
          P4array[i] = P4array[j];
          P4array[j] = temp;
        }
      }
    }
    for (i = 0; i < 3; i++) {
      printf("\nP4array[%d]=%lld\n", i, P4array[i]);
    }
  }
}


void *thread3()
{
  while (1) {
    long long int T3;
    T3 = rand() % 2001 + (-1000);
    return T3;
  }
}

int main()
{
  int status;
  int N, i;
  long long int T1 = 0, T3 = 0, *array, T2 = 1;
  pthread_t tid1, tid2, tid3, tid4;

  printf("Enter number of elements:");
  scanf("%d", &N);

  array = (int *) malloc(N * sizeof(long long int));
  if (array == NULL) {
    exit(0);
  }

  srand(time(NULL));

  for (i = 0; i < N; i++) {
    array[i] = (rand() % 201 + (-100));
    printf("%d\n", array[i]);
  }

  pthread_create(&tid1, NULL, thread1, NULL);
  pthread_create(&tid2, NULL, thread2, NULL);
  pthread_create(&tid3, NULL, thread3, NULL);
  pthread_create(&tid4, NULL, thread4, NULL);
  pthread_join(tid1, NULL);
  pthread_join(tid2, NULL);
  pthread_join(tid3, NULL);
  pthread_join(tid4, NULL);
  free(array);
  return 0;
}

> void *thread1(int N, long long int array[])
You can't invent your own parameter lists.
All thread functions are of the form
void *threadFunc(void *arg);

Why do all your thread functions have while(1) loops, when you have things like return in the middle of the loops?

I suggest a few simpler exercises along the lines of passing a string to a thread, which prints it out and returns a different string for main to print as well.