C fork dealing with global variable

Question

I\'m not understanding the output of this program:

#include 
#include 
#include 

int i = 0;

int main()
{
           


        

Answer 1

Try using pthreads if you want to create a thread inside the process for concurrent programming. The function you want is pthread_create and pthread_join for tidying up later.

Something like this:

#include 
#include 
#include 
#include 


int i = 0;

void *threadFunc(void *arg) 
{
    printf("%d\n",i);
}

int main()
{
    int j = 0;  
    int returnValue = 0;
    pthread_t* myThread = (pthread_t*) calloc(3, sizeof(pthread_t));;

    while(i < 3)
    {

        returnValue = pthread_create(&myThread[i], NULL, threadFunc, NULL);
        printf("main thread: %d\n",i);
        i++;

    }


    for(j = 0; j < 3; j++)
    {
        pthread_join(myThread[j], NULL); 

    }

    return 0;
}

But perhaps not, depending on your actual needs.