New Control Panel Applet

Hey there...

Recently I have been looking into creating new Control Panel applets in C.

I got this link from Msdn: Msdn Shell Stuff which seemed very helpful and tried to use their sample code. This however did not work...
I simplified their code to this, which still has a problem:

Code:

#include <cpl.h> 

BOOL WINAPI CALLBACK __declspec(dllexport) CPlApplet(HWND hwnd,UINT Msg,LONG lParam1,LONG lParam2) 
{ 
   CPLINFO * cp; 
   switch(Msg) { 
      case CPL_INIT: 
         //no memory to set, so do nothing... 
         return TRUE; 
      case CPL_GETCOUNT: 
         return 1;    //only one subprogram... 
      case CPL_INQUIRE: 
         cp = (CPLINFO*)lParam2; 
         cp->idIcon = IDMAINICON; 
         cp->idName = IDNAME; 
         cp->idInfo = IDDESCR; 
         cp->lData  = 0; 
         return 0; 
      case CPL_DBLCLK: 
         MessageBox(hwnd,"The message was correctly processed?","status",0); 
         break; 
   } 
   return FALSE; 
}

The problem is that when called from the Control Panel as it supposed to be, Explorer crashes. hmmm. Don't know why?
Using Messageboxes, saw that CPL_INIT was called, and that the crash was just after. There were no error logs, and I don't know how to track this down further.

The dll file generated had CPlApplet as entry-point, as I think it was supposed to...

Thanks for your time and trouble.

CPL_NEWINQUIRE Message

If the CPlApplet function processes this message successfully, it should return zero.

Assumably, if you don't handle this message you should return non-zero. If that is the case, the MSDN sample is wrong.

Then again, with this bit of inspired code, I wouldn't be too surprised.

Code:

HWND hwndCPL;      // handle to Control Panel window 
UINT uMsg;         // message 
LPARAM lParam1;    // first message parameter 
LPARAM lParam2;    // second message parameter 

LONG CALLBACK CPlApplet(hwndCPL, uMsg, lParam1, lParam2) 
{ 
    int i; 
    LPCPLINFO lpCPlInfo; 
...