- 1 year ago
Where is WinMain() in Win32 API implemented?
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In the Win32 API, the WinMain()
function is the entry point for a Windows application. It is typically implemented by the application developer in the source code of their application. The WinMain()
function is responsible for initializing the application, creating the application's main window, and entering the application's message loop.
Here is an example of how WinMain()
can be implemented in C++ using the Win32 API:
cpp#include <windows.h>
// Entry point of the application
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
// Step 1: Initialize application resources
// Register a window class
WNDCLASS wc = {};
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.lpszClassName = "MyWindowClass";
RegisterClass(&wc);
// Create the application's main window
HWND hWnd = CreateWindowEx(0, "MyWindowClass", "My Application", WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);
// Step 2: Display the window
ShowWindow(hWnd, nCmdShow);
// Step 3: Enter the message loop
MSG msg = {};
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
// Step 4: Cleanup and exit
return 0;
}
// Window procedure for the application's main window
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_DESTROY:
PostQuitMessage(0);
return 0;
// Handle other messages as needed
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
In this example, WinMain()
is the entry point and performs the following steps:
- Initialize application resources, such as registering a window class.
- Create the application's main window.
- Display the window using
ShowWindow()
. - Enter the message loop using
GetMessage()
, which retrieves and dispatches messages sent to the application's window procedure (WindowProc()
in this example). - When the window receives the
WM_DESTROY
message, the application posts a quit message usingPostQuitMessage(0)
to exit the message loop. - After the message loop exits,
WinMain()
returns, and the application terminates.
It's important to note that WinMain()
is specific to the Windows platform and the Win32 API. Other operating systems and frameworks may have different entry points and mechanisms for handling application initialization and message processing.