关于孙鑫视频教程Lesson1中返回值的问题
请教下各位大侠，本人初学VC,想问下以下代码（为孙鑫视频教程中的例程）中标红处的返回值具体各代表什么含义啊？尤其是第一个返回值
return msg.wParam ，为啥不是return msg.lParam呢？求高手正解

#include <windows.h>
#include <stdio.h>


LRESULT CALLBACK WinSunProc(
HWND hwnd, // handle to window
UINT uMsg, // message identifier
WPARAM wParam, // first message parameter
LPARAM lParam // second message parameter
);

int WINAPI WinMain(
HINSTANCE hInstance, // handle to current instance
HINSTANCE hPrevInstance, // handle to previous instance
LPSTR lpCmdLine, // command line
int nCmdShow // show state
)
{
WNDCLASS wndcls;
wndcls.cbClsExtra=0;
wndcls.cbWndExtra=0;
wndcls.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);
wndcls.hCursor=LoadCursor(NULL,IDC_CROSS);
wndcls.hIcon=LoadIcon(NULL,IDI_ERROR);
wndcls.hInstance=hInstance; //指定包含窗口过程的程序的实例句柄
wndcls.lpfnWndProc=WinSunProc; //定义回调函数
wndcls.lpszClassName="sunxin2006";
wndcls.lpszMenuName=NULL;
wndcls.style=CS_HREDRAW | CS_VREDRAW;
RegisterClass(&wndcls);

HWND hwnd;
hwnd=CreateWindow("sunxin2006","http://www.suRLAPPEnxin.org",WS_OVERLAPPEDWINDOW,
0,0,600,400,NULL,NULL,hInstance,NULL);

ShowWindow(hwnd,SW_SHOWNORMAL);
UpdateWindow(hwnd);

MSG msg;
while(GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;[b][/b]
}

LRESULT CALLBACK WinSunProc(
HWND hwnd, // handle to window
UINT uMsg, // message identifier
WPARAM wParam, // first message parameter
LPARAM lParam // second message parameter
)
{
switch(uMsg)
{
case WM_CHAR:
char szChar[20];
sprintf(szChar,"char code is %d",wParam);
MessageBox(hwnd,szChar,"char",MB_OK);
break;
case WM_LBUTTONDOWN:
MessageBox(hwnd,"mouse clicked","message",0);
HDC hdc;
hdc=GetDC(hwnd);
TextOut(hdc,0,50,"程序员之家",strlen("程序员之家"));
//ReleaseDC(hwnd,hdc);
break;
case WM_PAINT:
HDC hDC;
PAINTSTRUCT ps;
hDC=BeginPaint(hwnd,&ps);
TextOut(hDC,0,0,"http://www.sunxin.org",strlen("http://www.sunxin.org"));
EndPaint(hwnd,&ps);
break;
case WM_CLOSE:
if(IDYES==MessageBox(hwnd,"是否真的结束？","message",MB_YESNO))
{
DestroyWindow(hwnd);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd,uMsg,wParam,lParam); //除去，则窗口无法显示，只有进程显示。
}
return 0;[b][/b]
}

[解决办法]
第一个作为WinMain的返回值，第二个为窗口回调函数的返回值。
[解决办法]
都是返回值，通过返回值可以告知该函数的执行结果。return msg.wParam 而不是return msg.lParam则是不同的参数代表不同的信息啊
[解决办法]
WM_QUIT

WPARAM wParam
LPARAM lParam;

Parameters

wParam
Specifies the exit code given in the PostQuitMessage function.
lParam
This parameter is not used.

那是因为窗口销毁的消息lParam没用。
[解决办法]
MSG
The MSG structure contains message information from a thread's message queue.

typedef struct tagMSG {
HWND hwnd;
UINT message;
WPARAM wParam;
LPARAM lParam;

DWORD time;
POINT pt;
} MSG, *PMSG;
Members
hwnd
Handle to the window whose window procedure receives the message.
message
Specifies the message identifier.
wParam
Specifies additional information about the message. The exact meaning depends on the value of the message member.
lParam
Specifies additional information about the message. The exact meaning depends on the value of the message member.
time
Specifies the time at which the message was posted.
pt
Specifies the cursor position, in screen coordinates, when the message was posted




就是这个，就是返回的消息wParam的信息