An example of threading in C. Shows how one can pass results (via return or pointer argument)

c_lpthreads_example.c

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

void* t_routine(void* args){
	unsigned int i = 0;
	int a;
	printf("Running thread!\n");
	for(i=0;i<4000000000;i++){
		a = 2*2;
		if(i%1000000000==0){
			printf("%u\n", i);
		}
	}
	printf("Thread finished!\n");

	
	*((int*)args) = 42;

	int* ret = malloc(sizeof(int));
	*ret = 100;
	return ret;
}

int main(int argc, char const *argv[])
{
	/* code */
	const int N_THREADS = 8;
	pthread_t threads[N_THREADS];
	int* result = malloc(sizeof(int));
	void* status;

	int i = 0;
	printf("Launching!\n");
	for(i=0;i<N_THREADS;i++){
		pthread_create(&threads[i], NULL, t_routine, result);
	}

	for(i=0;i<N_THREADS;i++){
		pthread_join(threads[i], &status);
		printf("%p\n", status);
		printf("%d\n", *(int*)status);
		free(status);
	}

	printf("Done!\n");

	// printf("%p\n", result);
	printf("%d\n", *result);
	free(result);
	return 0;
}