warning C4244: “return”: 从“WPARAM”转换到“int”，可能丢失数据

[mqphk]

vs 2005 编译 windows 程序设计 第三章的简单程序
出现警告
hellowin.cpp(157) : warning C4244: “return”: 从“WPARAM”转换到“int”，可能丢失数据

哪位帮忙一下,感谢!


HELLOWIN.C

/*------------------------------------------------------------------------

HELLOWIN.C -- Displays "Hello, Windows 98!" in client area

(c) Charles Petzold, 1998

-----------------------------------------------------------------------*/

#include <windows.h>


LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;


int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,

PSTR szCmdLine, int iCmdShow)

{

static TCHAR szAppName[] = TEXT ("HelloWin") ;

HWND hwnd ;

MSG msg ;

WNDCLASS wndclass ;


wndclass.style = CS_HREDRAW | CS_VREDRAW ;

wndclass.lpfnWndProc = WndProc ;

wndclass.cbClsExtra = 0 ;

wndclass.cbWndExtra = 0 ;

wndclass.hInstance = hInstance ;

wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ;

wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ;

wndclass.hbrBackground= (HBRUSH) GetStockObject (WHITE_BRUSH) ;

wndclass.lpszMenuNam = NULL ;

wndclass.lpszClassName= szAppName ;


if (!RegisterClass (&wndclass))

{

MessageBox ( NULL, TEXT ("This program requires Windows NT!"),

szAppName, MB_ICONERROR) ;

return 0 ;

}

hwnd = CreateWindow( szAppName, // window class name

TEXT ("The Hello Program"), // window caption

WS_OVERLAPPEDWINDOW, // window style

CW_USEDEFAULT,// initial x position

CW_USEDEFAULT,// initial y position

CW_USEDEFAULT,// initial x size

CW_USEDEFAULT,// initial y size

NULL, // parent window handle

NULL, // window menu handle

hInstance, // program instance handle

NULL) ; // creation parameters



ShowWindow (hwnd, iCmdShow) ;

UpdateWindow (hwnd) ;



while (GetMessage (&msg, NULL, 0, 0))

{

TranslateMessage (&msg) ;

DispatchMessage (&msg) ;

}

return msg.wParam ;

}


LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)

{

HDC hdc ;

PAINTSTRUCT ps ;

RECT rect ;



switch (message)

{

case WM_CREATE:

PlaySound (TEXT ("hellowin.wav"), NULL, SND_FILENAME | SND_ASYNC) ;

return 0 ;


case WM_PAINT:

hdc = BeginPaint (hwnd, &ps) ;



GetClientRect (hwnd, &rect) ;



DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,

DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;

EndPaint (hwnd, &ps) ;

return 0 ;



case WM_DESTROY:

PostQuitMessage (0) ;

return 0 ;

}

return DefWindowProc (hwnd, message, wParam, lParam) ;

}

[tracing]

编译器的输出还是中文

[ccpaishi]

VS2005对于数据格式的要求变得很高了，前面加上(int)应该就可以了

[凤矶]

不用管
或int WINAPI WinMain
改成
void WINAPI WinMain， 去掉最后的返回

[WizardK]

return msg.wParam;这个何意？

[mqphk]

WINAPI WinMain
改成
void WINAPI WinMain， 去掉最后的返回

后

e:\cproj\windows程序设计\3hellowin\3hellowin\3hellowin.cpp(32) : error C2556: “void WinMain(HINSTANCE,HINSTANCE,LPSTR,int)”: 重载函数与“int WinMain(HINSTANCE,HINSTANCE,LPSTR,int)”只是在返回类型上不同
1> d:\program files\microsoft visual studio 8\vc\platformsdk\include\winbase.h(1875) : 参见“WinMain”的声明
1>e:\cproj\windows程序设计\3hellowin\3hellowin\3hellowin.cpp(32) : error C2371: “WinMain”: 重定义；不同的基类型
1> d:\program files\microsoft visual studio 8\vc\platformsdk\include\winbase.h(1875) : 参见“WinMain”的声明

3hellowin.cpp(334) : warning C4715: “WinMain”: 不是所有的控件路径都返回值

[thisisyjs]

return msg.wParam; --> return (int)msg.wParam;

[菜牛]

强制转换一下就可以了。

[mqphk]

感谢，thisisyjs．问题终于解决了。

[mqphk]

具体怎么改?

[cyw026]

同样问题~~~不过平时都没注意这些

[kuangdaxz]

我也遇到同样的问题，希望从这个帖子中找到解决方案！

[yuanji1]

hehe....