Basic Win16 dialog application which can be built using Visual C++.
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Win16 Dialog Application

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This application is an example Win16 dialog application. It uses a dialog resource and Windows dialog box functions for creating the dialog, meaning it can be edited using App Studio in Visual C++ (or the equivalent in other IDEs) rather than having to manually create controls at runtime.

The following changes from a standard Windows application are required for this to happen:

  • The dialog being used for the main window must have a class name associated with it. This is done by setting the "Registered Class" property on the dialog.
  • The Window class for the main window must have the "cbWndExtra" field set to "DLGWINDOWEXTRA", and the "lpszClassName" must match the class name you gave to the dialog resource. All other properties (e.g. the window procedure and icons) are set the same as you normally would for a Windows application.
  • The dialog window is created with "CreateDialog()" rather than "CreateWindow()". The "lpTemplate" parameter should be set to the resource ID of the dialog (not the class name of the dialog!), and the "lpDialogFunc" parameter should be set to NULL.
  • The application's message pump should call "IsDialogMessage()" on each message it gets. This is optional, but doing so means that the dialog behaves like a dialog, e.g. pressing the tab key moves focus to the next dialog control.
  • The "WM_CREATE" message handler includes some code to reposition the dialog before it is displayed. This is also optional, but if this isn't done then the dialog will always display in the centre of the main display. If two instances of the application are launched, the second instance could hide the first one.

Other than that, the application code is the same as that for a standard Windows application.

The application can be built using Visual C++ 1.5x. You can download Visual C++ 1.52 if you have a Visual Studio Subscription. If you don't have a subscription, you can download the Windows Server 2003 DDK which contains the 16 bit command line tools (most of which are from Visual C++ 1.52). The 16 bit binaries can be found in "bin\bin16" of the installed DDK, include files in "inc\inc16", and lib files in "lib\lib16". A number of the binaries come in two versions, one with and one without a "16" suffix, e.g. "cl.exe" and "cl16.exe". Despite the different filenames, the file contents are identical.

With a few small changes to the Makefile, the application will build with Microsoft C / C++ 7.0 and the Windows 3.1 SDK. It won't build with the Windows 3.0 SDK because the headers don't define some of the required types, and it does not have the "ver.h" header which is required for the version information resource.

Building the Application

To build the application with the Microsoft Visual C++ 1.5x GUI, go to "project", "open", then open "Win16Dlg.mak". To choose a debug or release build, go to "options" then "project". The project can be built using the "build" or "rebuild" toolbar items, or via the "project" menu.

To build the application from the command line with Visual C++ 1.5x, launch a command prompt, run the "MSVCVARS.BAT" file which can be found in the Visual C++ "bin" directory, and then navigate to the directory containing the Makefile. Run "nmake /f Win16Dlg.mak" to build. This also works with the Windows Server 2003 DDK, but instead of running "MSVCVARS.BAT", you will need to add the "bin16" directory to your "%PATH%" environment variable, "inc16" to "%INCLUDE%", and "lib16" to "%LIB%".

Smart Callbacks

This application makes use of so-called "smart callbacks". This means the data segment register is loaded from the stack segment register on entry to any callback function which is called by Windows. The result of this is that it is not necessary to list the callback functions in the application's module definition file, and it is not necessary to use "MakeProcInstance" to create a thunk when (e.g.) displaying a dialog box. In Visual C++ this is achieved by marking callback functions with the "__export" modifier, and using the "/GA /GEs /GEm" compiler options (optimise far function epilogs, load DS from SS, and increment BP on entry to the callback--required only for real mode stack walking support). You can also use the "/GEf" option, which means all far functions are given the code to load DS from SS regardless of whether they are callback functions. This is slightly less efficient, but does mean that callback functions don't require the "__export" modifier.

Refer to the Windows 1 Application for an example application which uses "MakeProcInstance" rather than smart callbacks.

Terms of Use

Refer to "License.txt" for terms of use.


If you have any problems or questions, please ensure you have read this readme. If you are still having trouble, you can get in contact.


  1. 2017-11-10: Version 1.0
  • Initial release.

Transmission Zero 2017-11-10