C++/CLI wrapper

no-reply@allegro.cc (shadyvillian) — Wed, 17 Aug 2016 05:38:22 +0000

Hi all,

I'm trying to create a CLI wrapper for allegro 5.2 using the latest nuget package so I can use allegro in c#. When I try to run my test console app, my app crashes on al_init(). When I say crash I mean the application just dies immediately with no exception or anything. Any Ideas?

namespace AllegroSharp
{
  public ref class Allegro
  {
    public:

    bool UseImageAddon;

    bool Initialize();
  };
}

.cpp

#include "Allegro.h"
#include "allegro5\allegro.h"
#include "allegro5\allegro_image.h"

bool AllegroSharp::Allegro::Initialize()
{
  bool allegroOk = al_init(); // crashes here
  bool imageAddonOk = UseImageAddon ? al_init_image_addon() : true;

  return allegroOk && imageAddonOk;
}

#SelectExpand
  1namespace AllegroSharpTest
  2{
  3    class Program
  4    {
  5        static void Main(string[] args)
  6        {
  7            Allegro allegro = new Allegro();
  8            Display display = new Display(1200, 800);
  9
 10            var statusOk = allegro.Initialize(); //crashes here
 11            var displayOk = display.Initialize();
 12
 13            Console.WriteLine($"Allegro ok: {statusOk} Display ok: {displayOk}");
 14
 15            Console.ReadKey();
 16
 17        }
 18    }
 19}

EDIT: I'm starting to the think it has something to do with the entry point. I put the no entry point flag for my dll so i could link it. I figured allegro would provide the entry point when the user of the dll calls allegro init. I'm trying to compile it with a dllmain function in my dll but the linker can't seem to find it.

no-reply@allegro.cc (SiegeLord) — Sat, 20 Aug 2016 20:22:06 +0000

You generally never want to call al_init from a library (see its documentation), so at the very least you should try calling al_install_system instead.

no-reply@allegro.cc (shadyvillian) — Mon, 22 Aug 2016 16:05:20 +0000

I was trying that but it seemed to crash as well. I think I supplied nullptr for the second parameter. Is that correct or should I use something else?

EDIT: It worked, thanks.

no-reply@allegro.cc (Mark Oates) — Wed, 24 Aug 2016 22:27:51 +0000

Proper Allegro Docs said:

Note: It is typically wrong to call al_init anywhere except the final game binary. In particular, do not call it inside a shared library unless you know what you're doing. In those cases, it is better to call al_install_system either with a NULL atexit_ptr, or with a pointer to atexit provided by the user of this shared library.

New news to me!