CreateWindow not working

[devrandom]

Hello,

I created this simple code, but it always returns 1.

Where's the problem?

expandcollapse popup

#include <stdio.h>
#include <windows.h>

int main(void)
{
    HINSTANCE instance;
    HWND handle;

    handle = CreateWindow (
                                "MainWClass",  // Class name
                                "Window!!",    // Title
                                WS_MINIMIZEBOX|// \
                                WS_CAPTION|    //  \__> style
                                WS_POPUP|      //  /
                                WS_SYSMENU,    // /
                                CW_USEDEFAULT, // Left
                                CW_USEDEFAULT, // Top
                                250,           // Width
                                250,           // Height
                                (HWND) NULL,
                                (HMENU) NULL,
                                instance,
                                NULL
                             );

    if (!handle)
    {
        return 1;
    }

    ShowWindow(handle, SW_SHOW);

    while (1)
    {
        UpdateWindow(handle);
    }

    return 0;
}

Note: it is C, not C++... Is this the problem?

I know only C, how can I create windows in C with Windows APIs?

Thank you

Edited March 14, 2011 by devrandom

[Mat]

You aren't initialising instance for a start. How about setting up a simple error catching mechanism. If you just use return GetLastError(); then look up the code on msdn then we would be a bit closer to finding out, saying that it just failed is not really enough.

Mat

[Richard Robertson]

It's fine to use C. The problem is that you are attempting to use "MainWClass" but I don't see where you registered this class anywhere.

[devrandom]

You aren't initialising instance for a start. How about setting up a simple error catching mechanism. If you just use return GetLastError(); then look up the code on msdn then we would be a bit closer to finding out, saying that it just failed is not really enough.

Mat

Thank you

It's fine to use C. The problem is that you are attempting to use "MainWClass" but I don't see where you registered this class anywhere.

Yes, I think this is the problem, I just modified a bit the MSDN example that evidently isn't working :S

How I can create a class? I looked at RegisterClass but being at the beginning with the Windows APIs, I have no idea on how to create the structure to pass as parameter for that function...

Is there any example on how to do this?

Sorry for my bad english

Edited March 14, 2011 by devrandom

[danielkza]

How I can create a class? I looked at RegisterClass but being at the beginning with the Windows APIs, I have no idea on how to create the structure to pass as parameter for that function...

Something like this should work (untested):

WNDCLASS class = {0};
class.style = 0;
class.hInstance = GetModuleHandle(NULL);
class.lpfnWndProc = (WNDPROC) myWindowProcedure;
class.lpszClassName = (LPCTSTR) _T("MyWindowClass");
// etc

Edited March 14, 2011 by danielkza

[devrandom]

What _T() is?

[Richard Robertson]

_T is a macro that will create a string that is either ANSI or Unicode depending on your platform.

I'm surprised anyone still uses it and doesn't just move to Unicode.

Edited March 15, 2011 by Richard Robertson

[danielkza]

_T is a macro that will create a string that is either ANSI or Unicode depending on your platform.

I'm surprised anyone still uses it and doesn't just move to Unicode.

I usually use Unicode exclusively, but for the example I thought I'd stick to the definition on MSDN.

[devrandom]

Mhhh I think there is a problem: when I use _T() my compiler says that isn't declared :|

[wraithdu]

Do I have to be the one to say it? Go buy a book and learn C. You clearly know next to nothing and are going to ask 100 more questions each time one is answered.