=========MAIN.C============================================
#include <stdlib.h>
#include <stdio.h>
#include "cstack.h"

void printyay()
{
  printf("Yay\n");
}

int main()
{
  cstack *data=malloc(sizeof(cstack));
  typedef void (*fp)();

  fp callme=NULL;

  char buf[50], *message=NULL;
  int num=27,*newnum=NULL;

  sprintf(buf, "Hello there.\n");

  /* Push data into stack */
  cpush(&data, &printyay, sizeof(fp));
  cpush(&data, &num, sizeof(int));
  cpush(&data, &buf, sizeof(char)* 50);

  /* Pop from data */
  message=(char*)cpop(&data);
  newnum=(int*) cpop(&data);
  callme=(fp)cpop(&data);

  printf("%s%d\n", message, *newnum);
  callme(); //<--- ERROR! This causes a segmentation fault

  free(callme);
  free(message);
  free(newnum);
  free(data);
  return 0;
}

=========CSTACK.C==========================================
#include "cstack.h"

void cpush(cstack** stackp, void* data, int size)
{
  (*stackp)->items++;
  (*stackp)->stack=realloc((*stackp)->stack, (*stackp)->items);
  (*stackp)->stack[(*stackp)->items-1]=malloc(size);
  memcpy(((*stackp)->stack)[(*stackp)->items-1], data, size);


}

void* cpop(cstack** stackp)
{
  void* data=NULL;
  (*stackp)->items--;
  data=((*stackp)->stack)[(*stackp)->items];
  (*stackp)->stack=realloc((*stackp)->stack, (*stackp)->items);
  if((*stackp)->items==0)
    {
    free((*stackp)->stack);
    (*stackp)->stack=NULL;
    }
  return data;
}

=========CSTACK.H==========================================
#ifndef _CSTACK_H_
#define _CSTACK_H_
#include <stdlib.h>
#include <string.h>
typedef struct cstack{
  void** stack;
  int items;
}cstack;

void cpush(cstack** stackp, void* data, int size);
void* cpop(cstack** stackp);

#endif