Question

Windows编程，同一个窗口类，创建两个窗口，销毁两个窗口程序不退出

代码：
#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <WindowsX.h>
#include <string.h>

#define WNDCLASS_NAME L"WNDCLASS1"

int giCount = 0;

LRESULT CALLBACK WinProc(
HWND hwnd,
UINT msg,
WPARAM wparam,
LPARAM lparam)
{
PAINTSTRUCT ps;
HDC hdc;

switch(msg)
{
case WM_CREATE:
return 0;
break;
case WM_PAINT:
hdc = BeginPaint(hwnd,&ps);
EndPaint(hwnd,&ps);
return 0;
break;
case WM_DESTROY:
--giCount;
if(giCount == 0)
{
PostQuitMessage(0);
}
return 0;
break;
default:
break;
}
return (DefWindowProc(hwnd,msg,wparam,lparam));
}

int WINAPI WinMain(
HINSTANCE hinstance,
HINSTANCE hprevinstance,
LPSTR lpcmdline,
int ncmdshow)
{
WNDCLASSEX wndcls;
HWND hwnd1;
HWND hwnd2;
MSG msg;

wndcls.cbSize = sizeof(WNDCLASSEX);
wndcls.cbClsExtra = 0;
wndcls.cbWndExtra = 0;
wndcls.hInstance = hinstance;
wndcls.lpfnWndProc = WinProc;
wndcls.style = CS_DBLCLKS | CS_OWNDC | CS_VREDRAW | CS_HREDRAW;
wndcls.lpszClassName = WNDCLASS_NAME;
wndcls.lpszMenuName = NULL;
wndcls.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndcls.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndcls.hCursor = LoadCursor(NULL,IDC_ARROW);
wndcls.hIconSm = LoadIcon(NULL,IDI_APPLICATION);

if(!RegisterClassEx(&wndcls))
{
return 0;
}

if(!(hwnd1 = CreateWindowEx(0,
WNDCLASS_NAME,
L"Your First Window",
WS_OVERLAPPEDWINDOW | WS_VISIBLE,
200,200,
400,400,
NULL,
NULL,
hinstance,
NULL)))
{
return 0;
}
++giCount;
if(!(hwnd2 = CreateWindowEx(0,
WNDCLASS_NAME,
L"Your Second Window",
WS_OVERLAPPEDWINDOW | WS_VISIBLE,
200,200,
400,400,
NULL,
NULL,
hinstance,
NULL)))
{
return 0;
}
++giCount;
while(true)
{
if(PeekMessage(&msg,hwnd1,0,0,PM_REMOVE) || PeekMessage(&msg,hwnd2,0,0,PM_REMOVE))
{
if(msg.message == WM_QUIT)
break;
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}

return msg.wParam;
}

Answer 1

while(true)
{
if(PeekMessage(&msg,hwnd1,0,0,PM_REMOVE) || PeekMessage(&msg,hwnd2,0,0,PM_REMOVE))
{
if(msg.message == WM_QUIT)
break;
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
消息循环没结束，再一个你的消息循环有问题呀：

if(PeekMessage(&msg,hwnd1,0,0,PM_REMOVE) || PeekMessage(&msg,hwnd2,0,0,PM_REMOVE)) 返回false的时候就会一直循环下去

追问

当两个窗口都销毁的时候，我在这个函数WinProc，有一个退出消息入队列，那么在
if(PeekMessage(&msg,hwnd1,0,0,PM_REMOVE) || PeekMessage(&msg,hwnd2,0,0,PM_REMOVE)) 这个if语句就会判断到WM_QUIT的消息，为什么进入不了这个break语句呢？

追答

PostQuitMessage 将WM_QUIT 发至线程的消息队列，你的消息只是从hwnd1 和hwnd2 来取，不一定能取到，
while(true)
{
if(PeekMessage(&msg, 0, 0, 0, PM_REMOVE) )
{
if(msg.message == WM_QUIT)
break;

TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
//这样写就对了，不过建议你使用GetMessage来做，这样不会使CPU一个核心达到100%，用PeekMessage一般的情况是做游戏实时渲染