create a GUi using window native API.

Question

hello, i am trying to create a GUI only use native windows api. i create projects in vs 2008 using win32 console project and win32 window project, and i used the sample code from Microsoft as below

    #include <windows.h> 

// Global variable 

HINSTANCE hinst; 

// Function prototypes. 

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int); 
InitApplication(HINSTANCE); 
InitInstance(HINSTANCE, int); 
LRESULT CALLBACK MainWndProc(HWND, UINT, WPARAM, LPARAM); 

// Application entry point. 

int WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, 
    LPSTR lpCmdLine, int nCmdShow) 
{ 
    MSG msg; 

    if (!InitApplication(hinstance)) 
        return FALSE; 

    if (!InitInstance(hinstance, nCmdShow)) 
        return FALSE; 

    BOOL fGotMessage;
    while ((fGotMessage = GetMessage(&msg, (HWND) NULL, 0, 0)) != 0 && fGotMessage != -1) 
    { 
        TranslateMessage(&msg); 
        DispatchMessage(&msg); 
    } 
    return msg.wParam; 
        UNREFERENCED_PARAMETER(lpCmdLine); 
} 

BOOL InitApplication(HINSTANCE hinstance) 
{ 
    WNDCLASSEX wcx; 

    // Fill in the window class structure with parameters 
    // that describe the main window. 

    wcx.cbSize = sizeof(wcx);          // size of structure 
    wcx.style = CS_HREDRAW | 
        CS_VREDRAW;                    // redraw if size changes 
    wcx.lpfnWndProc = MainWndProc;     // points to window procedure 
    wcx.cbClsExtra = 0;                // no extra class memory 
    wcx.cbWndExtra = 0;                // no extra window memory 
    wcx.hInstance = hinstance;         // handle to instance 
    wcx.hIcon = LoadIcon(NULL, 
        IDI_APPLICATION);              // predefined app. icon 
    wcx.hCursor = LoadCursor(NULL, 
        IDC_ARROW);                    // predefined arrow 
    wcx.hbrBackground = GetStockObject( 
        WHITE_BRUSH);                  // white background brush 
    wcx.lpszMenuName =  "MainMenu";    // name of menu resource 
    wcx.lpszClassName = "MainWClass";  // name of window class 
    wcx.hIconSm = LoadImage(hinstance, // small class icon 
        MAKEINTRESOURCE(5),
        IMAGE_ICON, 
        GetSystemMetrics(SM_CXSMICON), 
        GetSystemMetrics(SM_CYSMICON), 
        LR_DEFAULTCOLOR); 

    // Register the window class. 

    return RegisterClassEx(&wcx); 
} 

BOOL InitInstance(HINSTANCE hinstance, int nCmdShow) 
{ 
    HWND hwnd; 

    // Save the application-instance handle. 

    hinst = hinstance; 

    // Create the main window. 

    hwnd = CreateWindow( 
        "MainWClass",        // name of window class 
        "Sample",            // title-bar string 
        WS_OVERLAPPEDWINDOW, // top-level window 
        CW_USEDEFAULT,       // default horizontal position 
        CW_USEDEFAULT,       // default vertical position 
        CW_USEDEFAULT,       // default width 
        CW_USEDEFAULT,       // default height 
        (HWND) NULL,         // no owner window 
        (HMENU) NULL,        // use class menu 
        hinstance,           // handle to application instance 
        (LPVOID) NULL);      // no window-creation data 

    if (!hwnd) 
        return FALSE; 

    // Show the window and send a WM_PAINT message to the window 
    // procedure. 

    ShowWindow(hwnd, nCmdShow); 
    UpdateWindow(hwnd); 
    return TRUE; 

} 

then i got the errors:

1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(10) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(11) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(56) : error C2440: '=' : cannot convert from 'HGDIOBJ' to 'HBRUSH'
1>        Conversion from 'void*' to pointer to non-'void' requires an explicit cast
1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(57) : error C2440: '=' : cannot convert from 'const char [9]' to 'LPCWSTR'
1>        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(58) : error C2440: '=' : cannot convert from 'const char [11]' to 'LPCWSTR'
1>        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(64) : error C2440: '=' : cannot convert from 'HANDLE' to 'HICON'
1>        Conversion from 'void*' to pointer to non-'void' requires an explicit cast
1>c:\users\helloworld\documents\visual studio 2008\projects\motionwindow2\motionwindow2\main.cpp(92) : error C2664: 'CreateWindowExW' : cannot convert parameter 2 from 'const char [11]' to 'LPCWSTR'
1>        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>Build log was saved at "file://c:\Users\HelloWorld\Documents\Visual Studio 2008\Projects\motionwindow2\motionwindow2\Debug\BuildLog.htm"
1>motionwindow2 - 7 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

does anyone know what i did wrong? i didnt modify the code at all, and it is an empty project.

Thanks

Answer 1

The first error refers to line 10.

Thus, look at line 10:

InitApplication(HINSTANCE);

The declaration lacks a function result type.

And so on.

Cheers & hth.,

Answer 2

You've got several problems:

• The sample was C code and you are compiling as C++. Some questionable practices that were allowed in C are illegal in C++, such as implicit downcast from void* and implicit return type.
• The sample is ANSI, but your project settings are UNICODE.
• The sample is designed for NO_STRICT, but you are building with STRICT.