Question

我正在学习使用C ++编程窗口的MSDN课程，所以我尝试了他们的代码：

#ifndef UNICODE
#define UNICODE
#endif 

#include <windows.h>

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)
{
// Register the window class.
const wchar_t CLASS_NAME[]  = L"Sample Window Class";

WNDCLASS wc = { };

wc.lpfnWndProc   = WindowProc;
wc.hInstance     = hInstance;
wc.lpszClassName = CLASS_NAME;

RegisterClass(&wc);

// Create the window.

HWND hwnd = CreateWindowEx(
    0,                              // Optional window styles.
    CLASS_NAME,                     // Window class
    L"Learn to Program Windows",    // Window text
    WS_OVERLAPPEDWINDOW,            // Window style

    // Size and position
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

    NULL,       // Parent window    
    NULL,       // Menu
    hInstance,  // Instance handle
    NULL        // Additional application data
    );

if (hwnd == NULL)
{
    return 0;
}

ShowWindow(hwnd, nCmdShow);

// Run the message loop.

MSG msg = { };
while (GetMessage(&msg, NULL, 0, 0))
{
    TranslateMessage(&msg);
    DispatchMessage(&msg);
}

return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_DESTROY:
    PostQuitMessage(0);
    return 0;

case WM_PAINT:
    {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1));

        EndPaint(hwnd, &ps);
    }
    return 0;

}
return DefWindowProc(hwnd, uMsg, wParam, lParam);

}

因为我正在编译它：

g++ -c app.cpp -s app.o
g++ -o app.exe app.o -s -Wl,--subsystem,windows

然后我收到错误：

 undefined reference to WinMain@16

缺少什么？

Answer 1

wWinMain应为WinMain ....

编辑：好的，所以如果你想使用＆＃34;宽＆＃34; wWinMain的版本，我希望您需要定义-D_UNICODE，以便#include <windows.h>和其他位选择正确的部分。（或者，我想在您的来源中修改#define UNICODE到#define _UNICODE）

Answer 2

这是正确的代码：

#ifndef UNICODE
#define UNICODE
#endif 

#include <windows.h>

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)
{
// Register the window class.
const wchar_t CLASS_NAME[]  = L"Sample Window Class";

WNDCLASS wc = { };

wc.lpfnWndProc   = WindowProc;
wc.hInstance     = hInstance;
wc.lpszClassName = CLASS_NAME;

RegisterClass(&wc);

// Create the window.

HWND hwnd = CreateWindowEx(
    0,                              // Optional window styles.
    CLASS_NAME,                     // Window class
    L"Learn to Program Windows",    // Window text
    WS_OVERLAPPEDWINDOW,            // Window style

    // Size and position
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

    NULL,       // Parent window    
    NULL,       // Menu
    hInstance,  // Instance handle
    NULL        // Additional application data
    );

if (hwnd == NULL)
{
    return 0;
}

ShowWindow(hwnd, nCmdShow);

// Run the message loop.

MSG msg = { };
while (GetMessage(&msg, NULL, 0, 0))
{
    TranslateMessage(&msg);
    DispatchMessage(&msg);
}

return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_DESTROY:
    PostQuitMessage(0);
    return 0;

case WM_PAINT:
    {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1));

        EndPaint(hwnd, &ps);
    }
    return 0;

}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

链接器设置

g++ -c app.cpp -s app.o -lgdi32 -lmingw32
g++ -o app.exe app.o -s -Wl,--subsystem,windows -lgdi32 -lmingw32

在C ++中对WinMain @ 16的未定义引用

2 个答案: