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tom_mai78101

How do you create a Win32 window from Console Application?

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I have seen a few notable programs which can create windows from console applications. For instance, MCEdit (Minecraft World Editor), it first executes a console, then creates a window.

If I were to guess how it is called, it first goes through main(), then does something, then initializes and do CreateWindow().

How do you create a window without using WinMain() as the entry point? And what are the advantages to doing such things? (Like MCEdit, which is truly popular)

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Pretty much like normal. Create a console app ( /SUBSYSTEM:CONSOLE ), then:



[code]#include <iostream>
#include <windows.h>

long __stdcall WindowProcedure( HWND window, unsigned int msg, WPARAM wp, LPARAM lp )
{
switch(msg)
{
case WM_DESTROY:
std::cout << "\ndestroying window\n" ;
PostQuitMessage(0) ;
return 0L ;
case WM_LBUTTONDOWN:
std::cout << "\nmouse left button down at (" << LOWORD(lp)
<< ',' << HIWORD(lp) << ")\n" ;
// fall thru
default:
std::cout << '.' ;
return DefWindowProc( window, msg, wp, lp ) ;
}
}

int main()
{
std::cout << "hello world!\n" ;
const char* const myclass = "myclass" ;
WNDCLASSEX wndclass = { sizeof(WNDCLASSEX), CS_DBLCLKS, WindowProcedure,
0, 0, GetModuleHandle(0), LoadIcon(0,IDI_APPLICATION),
LoadCursor(0,IDC_ARROW), HBRUSH(COLOR_WINDOW+1),
0, myclass, LoadIcon(0,IDI_APPLICATION) } ;
if( RegisterClassEx(&wndclass) )
{
HWND window = CreateWindowEx( 0, myclass, "title",
WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT, 0, 0, GetModuleHandle(0), 0 ) ;
if(window)
{
ShowWindow( window, SW_SHOWDEFAULT ) ;
MSG msg ;
while( GetMessage( &msg, 0, 0, 0 ) ) DispatchMessage(&msg) ;
}
}
}[/code]


FYI, not my code, I pasted from [url="http://www.daniweb.com/software-development/cpp/threads/347901"]here.[/url]

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[quote name='ryan20fun' timestamp='1312822009' post='4846246']
they could have [url="http://www.halcyon.com/%7East/dload/guicon.htm"]attached[/url] a Console Window to a Win32 App.
[/quote]

That's what I do on my app's.

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Not relevant to the question, but worth noting that the sample Serapth posted suffers from a common [url="http://msdn.microsoft.com/en-us/library/ms644936%28v=vs.85%29.aspx"]GetMessage[/url] bug, and will go into an infinite loop if an error occurs:

[quote]If there is an error, the return value is -1.[/quote]

Beware if you're copy/pasting it.

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[quote name='mhagain' timestamp='1312825087' post='4846275']
Not relevant to the question, but worth noting that the sample Serapth posted suffers from a common [url="http://msdn.microsoft.com/en-us/library/ms644936%28v=vs.85%29.aspx"]GetMessage[/url] bug, and will go into an infinite loop if an error occurs:

[quote]If there is an error, the return value is -1.[/quote]

Beware if you're copy/pasting it.
[/quote]

Nobody takes it into account because [url=http://blog.airesoft.co.uk/2010/10/a-negative-experience-in-getting-messages/]it's nigh-on impossible for it to return -1[/url]

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[quote name='adeyblue' timestamp='1312829896' post='4846304']
[quote name='mhagain' timestamp='1312825087' post='4846275']
Not relevant to the question, but worth noting that the sample Serapth posted suffers from a common [url="http://msdn.microsoft.com/en-us/library/ms644936%28v=vs.85%29.aspx"]GetMessage[/url] bug, and will go into an infinite loop if an error occurs:

[quote]If there is an error, the return value is -1.[/quote]

Beware if you're copy/pasting it.
[/quote]

Nobody takes it into account because [url="http://blog.airesoft.co.uk/2010/10/a-negative-experience-in-getting-messages/"]it's nigh-on impossible for it to return -1[/url]
[/quote]

Still not a good idea to use known buggy code no matter how difficult it is to reproduce the result.

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[quote name='0Circle0' timestamp='1312831416' post='4846322']
[quote name='adeyblue' timestamp='1312829896' post='4846304']
[quote name='mhagain' timestamp='1312825087' post='4846275']
Not relevant to the question, but worth noting that the sample Serapth posted suffers from a common [url="http://msdn.microsoft.com/en-us/library/ms644936%28v=vs.85%29.aspx"]GetMessage[/url] bug, and will go into an infinite loop if an error occurs:

[quote]If there is an error, the return value is -1.[/quote]

Beware if you're copy/pasting it.
[/quote]

Nobody takes it into account because [url="http://blog.airesoft.co.uk/2010/10/a-negative-experience-in-getting-messages/"]it's nigh-on impossible for it to return -1[/url]
[/quote]

Still not a good idea to use known buggy code no matter how difficult it is to reproduce the result.
[/quote]

Plus we don't know what way it's going to behave on future vesions of Windows. We're essentially relying on an implementation detail that could change - the contract for GetMessage guarantees that you will get -1 if there is an error and gives two examples which could generate such an error. That is all. So we're relying on GetMessage to always behave the way it currently does with regard to the unlikelihood of it returning an error, despite the fact that this unlikelihood isn't specified as part of it's contract. Better to just follow the documentation instead (and as a bonus you get to contribute to helping keep hacky compatibility cruft out of Windows).

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