On 13.02.2012 20:13, Walter Bright wrote:
Hi Alf! Welcome!
Thanks.
On 2/12/2012 4:02 PM, Alf P. Steinbach wrote:
[snip]
* Improvement potential #5 -- The description of Windows prog.
Following main site's links to
[http://d-programming-language.org/windows.html],
I found a real monstrosity as an example of purportedly simplest possible
Windows GUI program. It's almost funny. Here is mine:
<code>
import std.c.windows.windows;
void main()
{
MessageBoxW( null, "Text", "Caption", MB_OK | MB_ICONINFORMATION );
}
</code>
[Just in passing, a practical tip: in Thunderbird (which you're using),
selecting all the text before hitting "Reply" prevents TB from removing
indents from code. They added the remove-indents behavior in version 2.
Nobody expects it, for why on Earth should it do that?, but it does.]
And here is how I built it:
<example>
[d:\dev\test\d]
> dmd minimal_gui.d -L-subsystem:windows
[d:\dev\test\d]
> dumpbin /headers minimal_gui.exe | find /i "sub"
3.10 subsystem version
2 subsystem (Windows GUI)
[d:\dev\test\d]
> minimal.d
</example>
Maybe with DMD tools something potentially bad happens here. However,
with
extant C++ compilers (and even old Borland C++ 5.5) this way of doing
things
works splendidly. So here is a definite improvement potential for the
web site
page with the monstrous code, and if the current tools don't handle it
well,
also for the the toolset. :-)
Good point, the Windows examples get less love than the other stuff.
He he.
On
the other hand, I don't think a simple main()/MessageBoxW() program
scales as a first program. It needs to be a WinMain(), and it needs to
show how to get a classic GUI program started up and shut down. The user
can then start hanging flesh on it for his own purposes.
Oh, that's just Microsoft propaganda-by-example.
In C and C++ the non-standard Microsoft specific WinMain startup
function technically only makes the programs formally incorrect for a
hosted implementation, and in practice it serves to make people accept
also other Microsoft lock-in things blindly, without questioning.
People are tricked into believing that this Microsoft standard-breaking
thing is needed because all Microsoft examples use it, and because
Microsoft's toolchain (but not e.g. the GNU toolchain) won't accept a
standard `main` for a GUI subsystem program, without use of not very
well documented options (MSVC linker option "/entry:mainCRTStartup").
In D, if the example code given on the D site is correct apart from the
result value bug, WinMain requires a lot of ugly boiler-plate code. Re
the bug, it's duplicated in the VisualD starter code for a new console
project, so such boiler-plate code is definitely undesirable... So, on
the Bright side, this is a real improvement opportunity :-).
The main problem (pun not intended) in C and C++ is that neither
standard `main` nor non-standard Microsoft `WinMain` provide the command
line arguments in Unicode. Standard `main` has `char` arguments, by
Windows convention encoded in Windows ANSI, which generally means data
loss and e.g. that some file names can't be passed. Microsoft `WinMain`
provides the arguments part of the command line, in Unicode, but not
split up into individual arguments.
I do not yet know the valid signatures for a D standard `main`.
But if those D signatures include one with a set of Unicode arguments,
then all is super-duper, and if not, then one must just do in D what one
must do in C and C++ for a real and standard-conforming program, namely
to use the Windows API to retrieve the arguments (if necessary).
- Alf (at very beginning of checking out the D language)
Thanks for taking the time to post these first experiences. It's often
hard for use to see the picture in the way a new user does.
I once, as a college lecturer, used to quip that one learns as long as
one has students... ;-)
Cheers & hth.,
- Alf
