Win API doesn't working

[kkez]

(and who needs them anyway).

Well, the latter is useless, but you need the first one to create a window but you're right, you can get it easily.

[sethjackson]

(and who needs them anyway).

Well, the latter is useless, but you need the first one to create a window but you're right, you can get them easily.

Actually you don't.

Consider this (it works).

This is a slightly modified version of the Win32 GUI template provided with C::B.

The only things that are changed is the entry point (main not WinMain),  GetModuleHandle(0) instead of hThisInstance, ShowWindow uses SW_SHOW instead of nCmdShow.

Code: cpp

#include <windows.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "CodeBlocksWindowsApp";

int main(int argc, char* argv[])
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = GetModuleHandle(0);
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Code::Blocks Template Windows App",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           GetModuleHandle(0),       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, SW_SHOW);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

[TDragon]

The only thing that is not quite right about it is that gcc does not report this as "illegal sequence" but simply fails silently, outputting an emtpy object file (which of course misses the WinMain function, as the linker correctly complains about).

Correct me if I'm wrong, but I thought this was because the invalid characters caused C::B to save an empty source file (rather than the fault belonging to GCC)?

[thomas]

You're right. I was convinced it only showed an empty file if the encoding was not good, but it really saves an empty file!

[Michael]

@Michael

Umm that topic was talking about wmain not WinMain. The entry point for GUI (console apps don't count) apps on Windows is WinMain.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/windows/windowreference/windowfunctions/winmain.asp

Yes, I know about WinMain (at least that it exists and what is it ), but I got the same WinMain error, by using wmain, WinMain and other that I have forgotten. I will look at this stuff a bit later when I will have some free time.

Best wishes,
Michael

[kkez]

(and who needs them anyway).

Well, the latter is useless, but you need the first one to create a window but you're right, you can get them easily.

Actually you don't.

You need the instance, in one way (using the WinMain argument) or another (using GetModuleHandle(NULL)). But you need it
The cmdShow can't be replaced the same way, since if you ShellExecute/CreateProcess one program and require it to start hidden or maximized or whatever, with that code you always show it...

[sethjackson]

(and who needs them anyway).

Well, the latter is useless, but you need the first one to create a window but you're right, you can get them easily.

Actually you don't.

You need the instance, in one way (using the WinMain argument) or another (using GetModuleHandle(NULL)). But you need it
The cmdShow can't be replaced the same way, since if you ShellExecute/CreateProcess one program and require it to start hidden or maximized or whatever, with that code you always show it...

Well can't you just do ShowWindow(wnd, SW_HIDE)..... :?  I read your post wrong. Sorry.  :oops: You need the instance, but how you go about getting it is another matter.

[kkez]

Well can't you just do ShowWindow(wnd, SW_HIDE)..... :?

Well, how do you know if it should be hidden or maximized or normal without the cmdShow that is passed to WinMain from ShellExecute or CreateProcess?

[sethjackson]

Well can't you just do ShowWindow(wnd, SW_HIDE)..... :?

Well, how do you know if it should be hidden or maximized or normal without the cmdShow that is passed to WinMain from ShellExecute or CreateProcess?

Hmm good question..... Maybe GetStartupInfo()?

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/getstartupinfo.asp
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/startupinfo_str.asp

[kkez]

You're right i didn't know that function.