Obtaining an Application's Instance Handle

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.1 and 3.0

SUMMARY

Many Windows API functions require an application's instance handle as a parameter. This article describes three methods that an application can use to obtain its instance handle.

MORE INFORMATION

Depending on the situation, an application might use any of the following three methods to obtain its instance handle:

1. The hInstance parameter to the WinMain procedure is the application's instance handle. The application can save this value in a global variable, making it available throughout the application.

2. The lParam parameter of the WM_CREATE message points to a CREATESTRUCT data structure, and the hInstance field of this structure is the application's instance handle. During the processing of the WM_CREATE message a window procedure can save this value in a static variable, as follows:

         hInst = ((LPCREATESTRUCT)lParam)->hInstance;
   

   This variable would then be available during all subsequent calls to the window procedure.

3. Given a window handle for one of its windows, an application can obtain its instance handle by calling the GetWindowWord function:

         GetWindowWord(hWnd, GWW_HINSTANCE)