string vs. w/char*

[Tyro]

== Quote from Denis Koroskin (2korden at gmail.com)'s article
> On Mon, 28 Feb 2011 19:35:47 +0300, Tyro[a.c.edwards]
<nospam at home.com>
> wrote:
> > On 2/28/2011 11:08 PM, J Chapman wrote:
> >> == Quote from Tyro[a.c.edwards] (nospam at home.com)'s article
> >>> Both implementations results in error code 1812 being
returned from
> >>> GetLastError. explanation of the code reads:
> >>>        ERROR_RESOURCE_DATA_NOT_FOUND
> >>>        1812 (0x714)
> >>>        The specified image file did not contain a resource
section.
> >>> The code I'm porting initially consisted of a resource.h
file, a
> >>> generic.rc file and two icons. I have not tried to include
the icons
> >>> and
> >>> generic.rc file in the compilation because I do not know how
to as yet
> >>> and I've only used half of the resource.h file: didn't think
I need the
> >>> whole thing. Could this be the reason for the error? If so
could you
> >>> direct me to the explanation of how to prepare these files
for
> >>> inclusion
> >>> in the compilation process?
> >>> Thanks,
> >>> Andrew
> >>
> >> You need to compile the .rc file (see
> >> http://www.digitalmars.com/ctg/rcc.html), then add the
resulting .res
> >> file
> >> to dmd's command line.
> >
> > Awesome, this does the trick. However I get get a "GP Fault"?
during
> > execution. Using windbg, I tracked it down to this piece of
code:
> >
> > void Create()
> > {
> >    _hwnd = CreateWindowExA(
> >      _exStyle,
> >      cast(const(char*))_wc.GetName(), // returns string
> >      cast(const(char*))_windowName,   // string variable
> >      _style,
> >      _x,
> >      _y,
> >      _width,
> >      _height,
> >      _hWndParent,
> >      _hMenu,
> >      _wc.GetInstance(),
> >      _data);
> >
> >      assert(_hwnd, "Internal error: Window Creation Failed.");
> > }
> >
> > The program craps at assert() but the error is generated. It
just
> > displays a dialog box with the message: "test.exe has stopped
working,
> > Windows is checking for a solution to the problem..."
> >
> > I'm thinking that _hwnd was never initialized and that assert
is access
> > a null pointer but I cannot be sure. Any suggestions or ideas?
> The
> >  cast(const(char*))_wc.GetName()
> line look *very* suspicious. You can't get a string and just
cast it to
> const(char)*. Most importantly, the string (most likely) is not
> null-terminated.
> What you need to do here is the following:
> auto className = toStringz(_ws.GetName());
> auto caption = toStringz(_windowName);
> and pass those 2 to the function.

Actually I've already tried that, it has no effect on the outcome.
>From your suggestion though, I've gone back and replace all the
cast(const(char*)) usage throughout the program. Final verdict:
the program still crashes it the same location. It actually never
returns from CreateWindowExA().

> Alternatively, you could make sure your strings are null-
terminated and
> pass the pointer directly (e.g. _windowName.ptr):
> string _windowName = "foo"; // null-terminated automatically
> string _caption = ("Hello, World" ~ "\0")[0..$-1]; // append
trailing zero
> to an existing string but exclude it from result (so that it's
not
> included in _caption.length)