Write native GUI applications for Windows

[Mike Parker]

On Monday, 18 December 2017 at 07:55:25 UTC, Andrey wrote:
> Hello!
> I have a question about creating native GUI applications for 
> Windows 7 or/and Windows 10.
> I know that exist DWT, DlangUI and other... But I'm interesting 
> in native GUI. If it will be C++ then I would use WinAPI from 
> SDK.
> And what about D? What should I do? Make some kind of wrapper 
> above C WinApi?

You can use the C Windows API out of the box:

import core.sys.windows.windows;

// And away you go

> I also know that on GitHub exists such wrapper 
> (https://github.com/AndrejMitrovic/DWinProgramming) but it is 
> old - last commit was 4 years ago.
>

The purpose of that repository was to port Petzold's examples to 
D. The Win32 API bindings (it's not a wrapper) were included to 
make building easier. I'm pretty sure somebody else set up a 
github mirror of the original DSource.org repository and Andrej 
simply copied it into his directory tree under the WindowsAPI 
directory. Meaning, I don't think the purpose of DWinProgramming 
was ever to actually host Windows bindings.

Regardless, third-party bindings are no longer necessary. All the 
examples in that repository should work (perhaps with minor 
changes) if you replace the win32.* imports with 
core.sys.windows. For example, the HelloMsg sample in the Chapter 
01 folder could use a couple f changes. toUTF16z is now part of 
std.utf, so no need for a custom implementation. And the versions 
of Runtime.initialize/terminate that take a delegate are 
deprecated. So this is what it should look like now:

module HelloMsg;

import core.runtime;
import std.utf;

import core.sys.windows.windows;

extern (Windows)
int WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR 
lpCmdLine, int iCmdShow)
{
     int result;
     try
     {
         Runtime.initialize();
         result = myWinMain(hInstance, hPrevInstance, lpCmdLine, 
iCmdShow);
         Runtime.terminate();
     }
     catch (Throwable o)
     {
         MessageBox(null, o.toString().toUTF16z, "Error", MB_OK | 
MB_ICONEXCLAMATION);
         result = 0;
     }

     return result;
}

int myWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR 
lpCmdLine, int iCmdShow)
{
     MessageBox(NULL, "Hello, Windows!", "Your Application", 0);
     return 0;
}

On the other hand, you can dispense with the WinMain nonsense 
just do this:

import core.runtime;
import std.utf;

import core.sys.windows.windows;

void main()
{
     MessageBox(null, "Hello, Windows!", "Your Application", 0);
}

Then compile with this to the same behavior as WinMain (i.e. no 
console window attached to the program):

dmd -L/SUBSYSTEM:windows HelloMsg.d

Or, when using the MS linker:

dmd -L/SUBSYSTEM:windows -L/ENTRY:mainCRTStartup -m64 HelloMsg.d 
user32.lib

Replace -m64 with -m32mscoff for 32-bit COFF output. Also note 
that when using the MS linker, you have to explicitly link with 
user32.lib. The same is true for the original WinMain version.