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D Programming Language 1.0


Last update Sun Dec 30 20:34:43 2012

D for Win32

This describes the D implementation for 32 bit Windows systems. Naturally, Windows specific D features are not portable to other platforms.

Instead of the:

#include <windows.h>

of C, in D there is:

import std.c.windows.windows;

Calling Conventions

In C, the Windows API calling conventions are __stdcall. In D, it is simply: 

extern (Windows)
{
	/* ... function declarations ... */
}

The Windows linkage attribute sets both the calling convention and the name mangling scheme to be compatible with Windows.

For functions that in C would be __declspec(dllimport) or __declspec(dllexport), use the export attribute: 

export void func(int foo);

If no function body is given, it's imported. If a function body is given, it's exported.

Windows Executables

Windows GUI applications can be written with D. A sample such can be found in \dmd\samples\d\winsamp.d

These are required:

  1. Instead of a main function serving as the entry point, a WinMain function is needed.
  2. WinMain must follow this form: 
    import std.c.windows.windows;

extern (C) void gc_init();
extern (C) void gc_term();
extern (C) void _minit();
extern (C) void _moduleCtor();
extern (C) void _moduleDtor();
extern (C) void _moduleUnitTests();

extern (Windows)
int WinMain(HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPSTR lpCmdLine,
	int nCmdShow)
{
    int result;

    gc_init();			// initialize garbage collector
    _minit();			// initialize module constructor table

    try
    {
	_moduleCtor();		// call module constructors
	_moduleUnitTests();	// run unit tests (optional)

	result = myWinMain(hInstance, hPrevInstance, lpCmdLine, nCmdShow);

	_moduleDtor();		// call module destructors
    }

    catch (Object o)		// catch any uncaught exceptions
    {
	MessageBoxA(null, cast(char *)o.toString(), "Error",
		    MB_OK | MB_ICONEXCLAMATION);
	result = 0;		// failed
    }

    gc_term();			// run finalizers; terminate garbage collector
    return result;
}

int myWinMain(HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPSTR lpCmdLine,
	int nCmdShow)
{
    /* ... insert user code here ... */
}
    The myWinMain() function is where the user code goes, the rest of WinMain is boilerplate to initialize and shut down the D runtime system.
  3. A .def (Module Definition File) with at least the following two lines in it: 
    EXETYPE NT
SUBSYSTEM WINDOWS
    Without those, Win32 will open a text console window whenever the application is run.
  4. The presence of WinMain() is recognized by the compiler causing it to emit a reference to __acrtused_dll and the phobos.lib runtime library.




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