#include <errno.h>
#include <error.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int main(void){	

	pthread_attr_t a;
	int result = 0;
	void *stackaddr = NULL;
	size_t stacksize = 0;
	int err;
	pid_t ret;
	
	ret = fork();
	if( ret != 0 ){
		wait(NULL);
		printf("In parent\n");
	} else if ( ret == -1 ) { 
		printf("Error forking.\n");
		exit(1);
	} else {
		printf("In child\n");
	}
	
	err = pthread_attr_init (&a);
	if (err){
		error(0, err, "pthread_attr_init failed");
		exit(1);
	}
	
	err = pthread_getattr_np (pthread_self (), &a);
	if (err){
		error (0, err, "pthread_getattr_np failed");
		exit(1);
	}
    
	err = pthread_attr_getstack (&a, &stackaddr, &stacksize);
	printf("&a=0x%x, stackaddr=0x%x, stacksize=0x%x\n",
        	(unsigned int)(&a),(unsigned int)stackaddr,stacksize);
	if (err){
		error (0, err, "pthread_attr_getstack failed");
		result = 1;
	} else if ((void *) &a < stackaddr || (void *) &a >= stackaddr + stacksize){
		error (0, 0, "pthread_attr_getstack returned range does not cover main's stack");
		result = 1;
	} else
	printf ("initial thread stack %p-%p (0x%zx)\n", 
		stackaddr, stackaddr + stacksize, stacksize);
	exit(0);
}