   .hinstance
  Could someone tell me what kind of object is stored in the wac.hInstance as I want to make a pointer to it but I don't know what type it should be.WNDCLASSEX wac;   wac.hInstance = GetModuleHandle(NULL);  
  It's an HINSTANCE :)   ;  It's an HINSTANCE, which is a handle, or opaque pointer. You shouldn't need to have a pointer to an HINSTANCE unless your have it as an out parameter (if you are using C++, then you would use a reference instead).What exactly are you trying to do?   ;  This isn't a DirectX API question - moved to For Beginners.Remember that MSDN documentation is your friend [wink]Cheers,Jack   ;  Trying to make an error window using Direct X  //------------------------------------------------------------------------------// ERROR_CHECK HEADER VERSION 0.1//------------------------------------------------------------------------------#include "Windows.h"class Error_check {public://create structure for window properties WNDCLASSEX wac; // set size   wac.cbSize = sizeof(WNDCLASSEX);   // set window style wac.style = CS_CLASSDC;   // set message handler wac.lpfnWndProc = NULL;  // set extra bytes for structure wac.cbClsExtra = 0;  // set extra bytes for window instance wac.cbWndExtra = 0;  // set unique HINSTANCE wac.hInstance = GetModuleHandle(NULL);  // set cursor wac.hCursor = LoadCursor(NULL, IDC_ARROW);   // set background wac.hbrBackground = NULL; // set windows Icon wac.hIcon = LoadIcon(NULL, IDI_APPLICATION); // set Icon Sm wac.hIconSm = LoadIcon(NULL, IDI_APPLICATION);// set class wac.lpszClassName = "Error_check;    // set menu  wac.lpszMenuName = NULL;  // register structuur RegisterClassEx(&wac); HINSTANCE * pointer_hin = wac.hInstance;Error_check(char* error_report){ // create window handle HWND window_handle;  // create window window_handle = CreateWindow("Error_check","Error_check",WS_POPUPWINDOW, 300,200,200,200,NULL,NULL,&pointer_hin,NULL); //error message box  MessageBox(window_handle,error_report, "Project-Mage error!", MB_OK|MB_ICONSTOP);} ~Error_check();}; ;  You haven't heard about DXTrace, have you?   