//---------------------------------------------------------------------------


#ifndef Unit1H
#define Unit1H
//---------------------------------------------------------------------------

#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>


HWND            hWnd=NULL;
HINSTANCE hInstance = NULL;
//---------------------------------------------------------------------------

class TForm1 : public TForm
{
__published:	// Von der IDE verwaltete Komponenten

        TButton *Button1;
        void __fastcall Button1Click(TObject *Sender);
private:	// Anwender-Deklarationen

public:		// Anwender-Deklarationen

        __fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------

extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------

#endif
[ /source]

/////////////////////////////////////////////////////////////////////////////

////////////////and here's the code of the *.cpp-File////////////////////////

/////////////////////////////////////////////////////////////////////////////


[ source]
void __fastcall TForm1::Button1Click(TObject *Sender)
{
 WNDCLASS	wc;		        // Windows class structure

 DWORD		dwExStyle;              // Window extended style

 DWORD		dwStyle;                // Window style

 RECT		WindowRect;             // Grabs rctangle upper left / lower right values

 WindowRect.left = (long)0;              // Set left value to 0

 WindowRect.right = (long)400;		// Set right value to requested width

 WindowRect.top = (long)0;               // Set top value to 0

 WindowRect.bottom = (long)400;       // Set bottom value to requested height


 	hInstance               = GetModuleHandle(NULL);		// Grab an instance for our window

	wc.style                = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;   // Redraw on size, and own DC for window

  //    wc.lpfnWndProc          = (WNDPROC) WndProc;			// WndProc handles messages

	wc.cbClsExtra           = 0;					// No extra window data

	wc.cbWndExtra           = 0;					// No extra window data

	wc.hInstance            = hInstance;				// Set the Instance

	wc.hIcon                = LoadIcon(NULL, IDI_WINLOGO);		// Load the default icon

	wc.hCursor              = LoadCursor(NULL, IDC_ARROW);		// Load the arrow pointer

	wc.hbrBackground        = NULL;					// No background required for GL

	wc.lpszMenuName		= NULL;					// We don't want a menu

	wc.lpszClassName	= "OpenGL";				// Set the class name


	if (!RegisterClass(&wc))					// Attempt to register the window class

	{
		MessageBox(NULL,"Failed to register the window class.","Error",MB_OK|MB_ICONEXCLAMATION);

	}
             if(!(hWnd = CreateWindowEx(WS_EX_APPWINDOW | WS_EX_WINDOWEDGE,          // Extended Style For The Window

                "OpenGL",				// Class name

		"Open GL Fenster",			// Window title

		WS_OVERLAPPEDWINDOW |		      	// Defined window style

	      	WS_CLIPSIBLINGS |			// Required window style

	    	WS_CLIPCHILDREN,			// Required window style

		0, 0,					// Window position

		(long) 640,                             	// Calculate window width

		(long) 480,	                                // Calculate window height

		NULL,					// No parent window

		NULL,					// No menu

		hInstance,				// Instance

		NULL)))					// Dont pass anything to WM_CREATE


        {

		MessageBox(NULL,"Konnte Fenster nicht initialisieren","ERROR",MB_OK|MB_ICONEXCLAMATION);
	}

}
//---------------------------------------------------------------------------

[ /source]