Keyboard Event Issue (aka: The Tales of a man who didn't knew how to code)

mumu1000

Hello everybody !
I'm having trouble using Allegro's Event system, and since i'm quite new to programming i can't figure out what's going wrong...

I'm trying to use a really simple test code:

#SelectExpand
  1#include <iostream>
  2#include "allegro5/allegro.h"
  3
  4int main(int argc, char **argv)
  5{
  al_init();
  ALLEGRO_DISPLAY * mainDisplay = al_create_display(1200,700);
  if(!al_install_keyboard())
  {
      cout << "Keyboard Installation Failed";
      return 1;
  }
  ALLEGRO_EVENT_SOURCE * keyboardEventSource = al_get_keyboard_event_source();
  ALLEGRO_EVENT_QUEUE * keyboardEventQueue = al_create_event_queue();
  ALLEGRO_EVENT * keyboardEvent;
  al_register_event_source(keyboardEventQueue,keyboardEventSource);
  do
  {
      while (!al_get_next_event(keyboardEventQueue,keyboardEvent))
      {
      } //I know this while loop is ugly, but thats just a test code OK ? ;)
      //It crashes here (when i press a key down)... :-/
  }while (keyboardEvent->type != ALLEGRO_EVENT_KEY_DOWN);
 24
  int key = keyboardEvent->keyboard.keycode;
  cout << key;
  return 0;
 28}

Everything works fine, until i press a key, then my program crashes with this error code: 0xC0000005 (no more comments)

Where did I make a mistake ?

Thanks for your help !

PS: I'm on Win10 and i'm using C::B

Edgar Reynaldo

mumu1000 said:

 ALLEGRO_EVENT * keyboardEvent;

That should be an ALLEGRO_EVENT, not an ALLEGRO_EVENT*. A pointer is an address, and in this case you didn't initialize the value either. So when al_wait_for_event returns and tries to fill in the data at the address of the ALLEGRO_EVENT you passed into it, it crashes, with an access violation.

mumu1000

Thank you alot (again ;p )

I think it will solve my problem !

Edgar Reynaldo

That should fix it.

Bump if you have questions.

DanielH

ALLEGRO_EVENT keyboardEvent;

...

// also change this to pass the address of the event object

~~while (!al_get_next_event(keyboardEventQueue, @keyboardEvent))~~

while (!al_get_next_event(keyboardEventQueue, &keyboardEvent))

bamccaig

DanielH said:

&keyboardEvent

FTFY. The address-of ('&') operator in C returns the address of its operand.

Niunio

Looks like DanielH is using Pascal or some other Wirth-lesque language.

mumu1000

Thanks alot for your replies !
I shall ask you if I have any questions ! (I will definitely have some later ;p)

Thread #617396. Printed from Allegro.cc