I get no compilation errors but when I debug, I get an access violation when the call to a class member's method.  I compile this in visual studio .net 2003 with the 3 files (this not an exact replica of the actual code) and the custom build steps to link them together.  Then I use the vs debugger.  I thought this was legal. :(

// main.d
import app;

int main(char[][] args)
{

app.App myapp = new app.App();
myapp.wnd.MsgBox("Test","Test", MB_OK);  // This line gets the violation

return 0;
}


//////////
// App.d

module app;

import window;

class App
{
public:
Window wnd;
}


////////////
// Window.d

module window;

import std.c.windows.windows;

class Window
{
public:
HANDLE hwnd;

void MsgBox(LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
{
MessageBoxA(null, lpText, lpCaption, uType);
return;
}
}

Hi,

The problem here is that in App.d you've declared an instance of the Window class, but haven't initialised it. You need to write a constructor for App which creates a new Window:

> //////////
> // App.d
>
> module app;
>
> import window;
>
> class App
> {
> public:
> Window wnd;
+ this()
+ {
+    wnd = new Window();
+ }
> }

On Sun, 20 Mar 2005 17:27:29 +0000 (UTC), NewtoD <NewtoD_member@pathlink.com> wrote:

> I get no compilation errors but when I debug, I get an access violation when the
> call to a class member's method.  I compile this in visual studio .net 2003 with
> the 3 files (this not an exact replica of the actual code) and the custom build
> steps to link them together.  Then I use the vs debugger.  I thought this was
> legal. :(
>
> // main.d
> import app;
>
> int main(char[][] args)
> {
>
> app.App myapp = new app.App();
> myapp.wnd.MsgBox("Test","Test", MB_OK);  // This line gets the violation
>
> return 0;
> }
>
>
> //////////
> // App.d
>
> module app;
>
> import window;
>
> class App
> {
> public:
> Window wnd;
> }
>
>
> ////////////
> // Window.d
>
> module window;
>
> import std.c.windows.windows;
>
> class Window
> {
> public:
> HANDLE hwnd;
>
> void MsgBox(LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
> {
> MessageBoxA(null, lpText, lpCaption, uType);
> return;
> }
> }
>
>



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Thank you so much!  That did it.  So unlike c++, you must use the new keyword to initialize an instance whether its a pointer or not?

In article <opsnx6jhgd08qma6@mjolnir.spamnet.local>, Alex Stevenson says...
>
>Hi,
>
>The problem here is that in App.d you've declared an instance of the Window class, but haven't initialised it. You need to write a constructor for App which creates a new Window:
>
>> //////////
>> // App.d
>>
>> module app;
>>
>> import window;
>>
>> class App
>> {
>> public:
>> Window wnd;
>+ this()
>+ {
>+    wnd = new Window();
>+ }
>> }
>
>On Sun, 20 Mar 2005 17:27:29 +0000 (UTC), NewtoD <NewtoD_member@pathlink.com> wrote:
>
>> I get no compilation errors but when I debug, I get an access violation
>> when the
>> call to a class member's method.  I compile this in visual studio .net
>> 2003 with
>> the 3 files (this not an exact replica of the actual code) and the
>> custom build
>> steps to link them together.  Then I use the vs debugger.  I thought
>> this was
>> legal. :(
>>
>> // main.d
>> import app;
>>
>> int main(char[][] args)
>> {
>>
>> app.App myapp = new app.App();
>> myapp.wnd.MsgBox("Test","Test", MB_OK);  // This line gets the violation
>>
>> return 0;
>> }
>>
>>
>> //////////
>> // App.d
>>
>> module app;
>>
>> import window;
>>
>> class App
>> {
>> public:
>> Window wnd;
>> }
>>
>>
>> ////////////
>> // Window.d
>>
>> module window;
>>
>> import std.c.windows.windows;
>>
>> class Window
>> {
>> public:
>> HANDLE hwnd;
>>
>> void MsgBox(LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
>> {
>> MessageBoxA(null, lpText, lpCaption, uType);
>> return;
>> }
>> }
>>
>>
>
>
>
>-- 
>Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

Thank you so much, that did it!  Basically, all instances must be initialized
with the new keyword, pointer or not?
:)


In article <opsnx6jhgd08qma6@mjolnir.spamnet.local>, Alex Stevenson says...
>
>Hi,
>
>The problem here is that in App.d you've declared an instance of the Window class, but haven't initialised it. You need to write a constructor for App which creates a new Window:
>
>> //////////
>> // App.d
>>
>> module app;
>>
>> import window;
>>
>> class App
>> {
>> public:
>> Window wnd;
>+ this()
>+ {
>+    wnd = new Window();
>+ }
>> }
>
>On Sun, 20 Mar 2005 17:27:29 +0000 (UTC), NewtoD <NewtoD_member@pathlink.com> wrote:
>
>> I get no compilation errors but when I debug, I get an access violation
>> when the
>> call to a class member's method.  I compile this in visual studio .net
>> 2003 with
>> the 3 files (this not an exact replica of the actual code) and the
>> custom build
>> steps to link them together.  Then I use the vs debugger.  I thought
>> this was
>> legal. :(
>>
>> // main.d
>> import app;
>>
>> int main(char[][] args)
>> {
>>
>> app.App myapp = new app.App();
>> myapp.wnd.MsgBox("Test","Test", MB_OK);  // This line gets the violation
>>
>> return 0;
>> }
>>
>>
>> //////////
>> // App.d
>>
>> module app;
>>
>> import window;
>>
>> class App
>> {
>> public:
>> Window wnd;
>> }
>>
>>
>> ////////////
>> // Window.d
>>
>> module window;
>>
>> import std.c.windows.windows;
>>
>> class Window
>> {
>> public:
>> HANDLE hwnd;
>>
>> void MsgBox(LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
>> {
>> MessageBoxA(null, lpText, lpCaption, uType);
>> return;
>> }
>> }
>>
>>
>
>
>
>-- 
>Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

Yes - In D all class objects are references - they behave like C++ pointers/references all the time - it takes a little getting used to, but once you've done a few it becomes second nature.

I'm pretty sure if I wrote C++ today I'd end up with lots of memory leaks because I'd forget to delete all the class objects I new'd.

Alex

On Sun, 20 Mar 2005 18:19:29 +0000 (UTC), NewtoD <NewtoD_member@pathlink.com> wrote:

> Thank you so much, that did it!  Basically, all instances must be initialized
> with the new keyword, pointer or not?
> :)
>
>
> In article <opsnx6jhgd08qma6@mjolnir.spamnet.local>, Alex Stevenson says...
>>
>> Hi,
>>
>> The problem here is that in App.d you've declared an instance of the
>> Window class, but haven't initialised it. You need to write a constructor
>> for App which creates a new Window:
>>
>>> //////////
>>> // App.d
>>>
>>> module app;
>>>
>>> import window;
>>>
>>> class App
>>> {
>>> public:
>>> Window wnd;
>> + this()
>> + {
>> +    wnd = new Window();
>> + }
>>> }
>>
>> On Sun, 20 Mar 2005 17:27:29 +0000 (UTC), NewtoD
>> <NewtoD_member@pathlink.com> wrote:
>>
>>> I get no compilation errors but when I debug, I get an access violation
>>> when the
>>> call to a class member's method.  I compile this in visual studio .net
>>> 2003 with
>>> the 3 files (this not an exact replica of the actual code) and the
>>> custom build
>>> steps to link them together.  Then I use the vs debugger.  I thought
>>> this was
>>> legal. :(
>>>
>>> // main.d
>>> import app;
>>>
>>> int main(char[][] args)
>>> {
>>>
>>> app.App myapp = new app.App();
>>> myapp.wnd.MsgBox("Test","Test", MB_OK);  // This line gets the violation
>>>
>>> return 0;
>>> }
>>>
>>>
>>> //////////
>>> // App.d
>>>
>>> module app;
>>>
>>> import window;
>>>
>>> class App
>>> {
>>> public:
>>> Window wnd;
>>> }
>>>
>>>
>>> ////////////
>>> // Window.d
>>>
>>> module window;
>>>
>>> import std.c.windows.windows;
>>>
>>> class Window
>>> {
>>> public:
>>> HANDLE hwnd;
>>>
>>> void MsgBox(LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
>>> {
>>> MessageBoxA(null, lpText, lpCaption, uType);
>>> return;
>>> }
>>> }
>>>
>>>
>>
>>
>>
>> --
>> Using Opera's revolutionary e-mail client: http://www.opera.com/m2/
>
>



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