clone.c

#define _GNU_SOURCE

#include <sched.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>

#define STACK_SIZE 1024*1024

int func(void* param) {
	printf("I am func, pid %d\n", getpid());
	return 0;
}

int main(int argc, char const *argv[]) {
	printf("I am main, pid %d\n", getpid());	

	void* ptr = malloc(STACK_SIZE);

	printf("I am calling clone\n");		
	int res = clone(func, ptr + STACK_SIZE, CLONE_VM, NULL);

	if (res == -1) {
		printf("clone error: %d", errno);
	} else {
		printf("I created child with pid: %d\n", res);
	}

	printf("Main done, pid %d\n", getpid());		
	return 0;
}