问题描述
我一直在尝试使用WinAPI创建一个简单的窗口,它会编译并链接一些警告,当我打开程序时,该窗口会显示出来,但是当我尝试与之交互时,会播放一个Windows警告声并它不允许我使用该窗口,甚至不能将其关闭,而必须使用任务管理器。
要编译它,我在命令行中使用Microsoft的“ cl.exe”:
cl /c window.c
并且警告是:
window.c(39): warning C4133: 'function': incompatible types,from 'LPSTR' to 'HINSTANCE'
window.c(40): warning C4133: 'function': incompatible types,from 'LPSTR' to 'HINSTANCE'
window.c(41): warning C4047: '=': 'HBrush' differs in levels of indirection from 'int'
crinkler /NODEFAULTLIB /ENTRY:main /SUSBYstem:WINDOWS /TINYHEADER /TINYIMPORT /OUT:c.exe window.obj kernel32.lib user32.lib
警告是:
: warning LNK: Entry point not at start of section,jump necessary
我正在使用的代码是:
#include <windows.h>
#define WINDOW_STYLE WS_VISIBLE+WS_OVERLAPPEDWINDOW-WS_THICKFRAME-WS_MAXIMIZE
#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 480
static const char* window_name = "My Window";
RECT window_rect = {0,WINDOW_HEIGHT,WINDOW_WIDTH};
LRESULT CALLBACK WindowProc(HWND hwnd,UINT uMsg,WParaM wParam,LParaM lParam)
{
switch(uMsg)
{
case WM_CLOSE:
PostQuitMessage(0);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
}
return DefWindowProcA(hwnd,uMsg,wParam,lParam);
}
int main()
{
int ret = 0;
HMODULE instance = GetModuleHandleA(NULL);
AdjustwindowRect(&window_rect,WINDOW_STYLE,FALSE);
WNDCLASSEXA window_class;
window_class.cbSize = 48;
window_class.style = CS_OWNDC|CS_HREDRAW|CS_VREDRAW;
window_class.lpfnWndProc = WindowProc;
window_class.cbClsExtra = 0;
window_class.cbWndExtra = 0;
window_class.hInstance = instance;
window_class.hIcon = LoadIconA(IDI_APPLICATION,0);
window_class.hCursor = LoadCursorA(IDI_APPLICATION,0);
window_class.hbrBackground = COLOR_WINDOW;
window_class.lpszMenuName = 0;
window_class.lpszClassName = window_name;
window_class.hIconSm = 0;
if (RegisterClassExA(&window_class)) {
HWND window = CreateWindowExA(
0,window_name,CW_USEDEFAULT,window_rect.right - window_rect.left,window_rect.bottom - window_rect.top,instance,NULL);
ShowWindow(window,SW_SHOW);
UpdateWindow(window);
MSG msg;
while(1)
{
if (PeekMessageA(&msg,PM_REMOVE)) {
if (msg.message == WM_QUIT) {
ExitProcess(0);
break;
} else {
TranslateMessage(&msg);
dispatchMessage(&msg);
}
}
}
} else {
ret = 1;
}
ExitProcess(0);
return ret;
}
有人知道如何解决吗?谢谢。
解决方法
以下行不执行您认为的操作:
#define WINDOW_STYLE WS_VISIBLE+WS_OVERLAPPEDWINDOW-WS_THICKFRAME-WS_MAXIMIZE
虽然有点普遍,有时甚至会产生正确的值,但这是实现位操作的一种非常脆弱的方法。在这种情况下,表达式扩展为:
0x10000000L + 0x00CF0000L - 0x00040000L - 0x01000000L
这将产生值0xFFCB0000L
1 (由于不小心使用了WS_MAXIMIZE
而不是WS_MAXIMIZEBOX
)。这将转换为具有以下样式的窗口:
-
WS_POPUP
-
WS_CHILD
(请注意,它已经与WS_POPUP
互斥) -
WS_ICONIC
-
WS_VISIBLE
-
WS_DISABLED
- ...
WS_DISABLED
:该窗口最初被禁用。 已禁用的窗口无法接收来自用户的输入。要在创建窗口后更改此设置,请使用EnableWindow
功能。
这说明了为什么无法与窗口进行交互。修复很简单:使用按位运算符而不是算术运算符进行位操作:
#define WINDOW_STYLE (WS_VISIBLE | WS_OVERLAPPEDWINDOW & ~WS_THICKFRAME & ~WS_MAXIMIZE)
1 事实上,没有定义有符号溢出的行为。