Is it okay to free a memory that was malloc'd in a different function?

Question

When I have the following for the main function, race happens because of i.

...
for(i = 0; i < 30; i++){
    pthread_create(&tid[i], NULL, thread, &i);
}
...

To avoid this, I malloc'd a size of int and then used it to pass the argument instead of &i. And then I used the value and then freed it in the thread function. Does this correctly free without memory leak? (The following is the new code)

void *thread(void *vargp){
    int n = *((int *)vargp);
    free(vargp);
    pthread_detach(pthread_self());
    printf("%d\n",n);
}

void main(){
    int i;
    pthread_t tid[20];
    for(i = 0; i < 20; i++){
        int *n = (int *) malloc(sizeof(int));
        *n = i;
        pthread_create(&tid[i], NULL, thread, n);
    }
    sleep(1);
}

Answer 1

The short answer - yes. As long as everything you malloc ed is eventually free d once and only once, it doesn't matter that the malloc and free happen in different functions, or even different threads.