Thread stack in heap (pthreads)

I had known that a thread has a stack. But never thought where is this stack lie in the memory?

Well, it should be process stack. But you can set the thread stack to a heap area.

How to do that?

#include "pthread.h"
#include "stdio.h"
#include "unistd.h"

pthread_mutex_t mutex1;

void* foo(void *arg)
{
int arr[1024*8];

int x = 0;
while(x++ < (8*1024) )
{ arr[x] = x; }

pthread_mutex_lock(&mutex1);
puts("Thread created");
pthread_mutex_unlock(&mutex1);
}

int main()
{
int *p;
void *ret;

p = malloc(1024);

free(p);

pthread_attr_t attr;

pthread_attr_setstack(&attr, p, 2);

pthread_t thread1;

pthread_create(&thread1, NULL, foo, NULL);

pthread_join(thread1, &ret);

free(p);

return 0;
}

But still I am not very sure of this concept.

Stay tuned for more!