🔒 Locked

Direct Input acces violation

Started by cpp boy Dec 18, 2003 at 6:47 PM 8 replies 700+ views

Original Post

Dec 18, 2003 at 6:47 PM

Ok. I got the book Windows Game Programming for dummies and I''m at the direct input part. The current stade of my directx sdks are the one that are included whit Microsoft Visual C++ 6.0. I''m not sure what version they are because there is no version on .h files but I''m assuming thats its the version 6 or 5. Here is the code of direct Input I''m using. #define INITGUID #include <windows.h> #include <dinput.h> #include <objbase.h> HINSTANCE hInstance; HWND hwnd; LPDIRECTINPUT lpdi; LPDIRECTINPUTDEVICE lpdikey; // Here is some codes about creating the window int Init() // this is where I''m implementing my direct Input code { if(DirectInputCreate(hInstance, DIRECTINPUT_VERSION, &lpdi, NULL) != DI_OK) { MessageBox(NULL, "Error", "Error", MB_OK | MB_ICONERROR); } lpdi->CreateDevice(GUID_SysKeyboard, &lpdikey, NULL); lpdikey->SetCooperativeLevel(hwnd, DISCL_BACKGROUND | DISCL_NONEXCLUSIVE); return 0; } Kevin

JoeyBlow2

Dec 18, 2003 at 7:07 PM

Which line is giving you the access violation?

cpp boy

Dec 21, 2003 at 11:52 AM

Normally the line : lpdikey->SetCooperativeLevel(hwnd, DISCL_BACKGROUND | DISCL_NONEXCLUSIVE);

is setting me a probleme but I have an empression that my direct Input is setting as I want to do.

Kevin

cpp boy

Dec 22, 2003 at 9:26 AM

So I guess no one of you is able to help whit my probleme.

Kevin

Mezz

Dec 22, 2003 at 9:48 AM

Have you tried checking the return value from the CreateDevice() call?
It might be failing and leaving you with an invalid lpdikey pointer.

-Mezz

cpp boy

Dec 23, 2003 at 11:05 AM

by the return value do you mean something like this :

if(lpdi)
lpdi->release();

cause if so when I try to do this it doesn''t work.

also I''ve tried this :

lpdi->release()

ans it didn''t work. But it had work for

if(lpdd) // Direct Draw
lpdd->release();

so thats about it.

Dave Hunt

Dec 23, 2003 at 11:11 AM

quote:

by the return value do you mean something like this :

if(lpdi)
lpdi->release();

cause if so when I try to do this it doesn''t work.

also I''ve tried this :

lpdi->release()

ans it didn''t work. But it had work for

if(lpdd) // Direct Draw
lpdd->release();

so thats about it.

You need to initialize lpdi and lpdikey to NULL when you declare them. Otherwise, they could have garbage in them and your code will think they got set by the create calls.

But what Mezz was refering to was the line:


lpdi->CreateDevice(GUID_SysKeyboard, &lpdikey, NULL);

You aren''t checking that call for failure like you did the DirectInputCreate call.

Pipo DeClown

Dec 23, 2003 at 11:44 AM

Have you tried using the newer versions of DI?

LPDIRECTINPUT8 g_lpDI; LPDIRECTINPUTDEVICE8 g_lpDIDevice;

.. and put this:
g_lpDIDevice->SetDataFormat(&c_dfDIKeyboard);

.. Before the SetCoo..() function.

--
You''re Welcome,
Rick Wong
- sitting in his chair doing the most time-consuming thing..

VolkerG

Dec 23, 2003 at 2:02 PM

First: Make sure you get the debug runtimes and watch the debug output.
Second: As mentioned before, test the return values (the HRESULT).
Third: Use FAILED() and co. to check for errors, not ... != *_OK.

johnnyBravo

Dec 24, 2003 at 9:37 AM

did you check that you have initialised the program first, like the windows creation etc, ive done that many times...

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.