标签：return Windows hWnd C++ hInstance wcex NULL Hello

microsoft官网文档 C++ 编写的 Windows 窗口 Hello,World 程序

// HelloWindowsDesktop.cpp
// compile with: /D_UNICODE /DUNICODE /DWIN32 /D_WINDOWS /c
#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>
// Global variables
// The main window class name.
static TCHAR szWindowClass[] = _T("DesktopApp");
// The string that appears in the application's title bar.
static TCHAR szTitle[] = _T("Windows Desktop Guided Tour Application");
HINSTANCE hInst;
// Forward declarations of functions included in this code module:
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int CALLBACK WinMain(
   _In_ HINSTANCE hInstance,
   _In_opt_ HINSTANCE hPrevInstance,
   _In_ LPSTR     lpCmdLine,
   _In_ int       nCmdShow
) {
    WNDCLASSEX wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, IDI_APPLICATION);
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = NULL;
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, IDI_APPLICATION);
    if (!RegisterClassEx(&wcex)) {
        MessageBox(NULL,
                 _T("Call to RegisterClassEx failed!"),
                 _T("Windows Desktop Guided Tour"),
                 NULL);
        return 1;
    }
    // Store instance handle in our global variable
    hInst = hInstance;
    // The parameters to CreateWindow explained:
    // szWindowClass: the name of the application
    // szTitle: the text that appears in the title bar
    // WS_OVERLAPPEDWINDOW: the type of window to create
    // CW_USEDEFAULT, CW_USEDEFAULT: initial position (x, y)
    // 500, 100: initial size (width, length)
    // NULL: the parent of this window
    // NULL: this application does not have a menu bar
    // hInstance: the first parameter from WinMain
    // NULL: not used in this application
    HWND hWnd = CreateWindow(
          szWindowClass,
          szTitle,
          WS_OVERLAPPEDWINDOW,
          CW_USEDEFAULT, CW_USEDEFAULT,
          500, 100,
          NULL,
          NULL,
          hInstance,
          NULL
       );
    if (!hWnd) {
        MessageBox(NULL,
                 _T("Call to CreateWindow failed!"),
                 _T("Windows Desktop Guided Tour"),
                 NULL);
        return 1;
    }
    // The parameters to ShowWindow explained:
    // hWnd: the value returned from CreateWindow
    // nCmdShow: the fourth parameter from WinMain
    ShowWindow(hWnd,
          nCmdShow);
    UpdateWindow(hWnd);
    // Main message loop:
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int) msg.wParam;
}
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
    PAINTSTRUCT ps;
    HDC hdc;
    TCHAR greeting[] = _T("Hello, Windows desktop!");
    switch (message) {
        case WM_PAINT:
              hdc = BeginPaint(hWnd, &ps);
        // Here your application is laid out.
        // For this introduction, we just print out "Hello, Windows desktop!"
        // in the top left corner.
        TextOut(hdc,
                 5, 5,
                 greeting, _tcslen(greeting));
        // End application-specific layout section.
        EndPaint(hWnd, &ps);
        break;
        case WM_DESTROY:
              PostQuitMessage(0);
        break;
        default:
              return DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }
    return 0;
}

标签：return,Windows,hWnd,C++,hInstance,wcex,NULL,Hello
来源： https://www.cnblogs.com/beanflame/p/14675323.html

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