Hi, I have always programmed in dos using ANSI C++ and using the STL functions. As I know every program should have a "main()" function. But then how is it that c++ programs for windows start with "WinMain()" ? Did Bjarne Stroustrup add this substitute for main to the language? becuase otherwise how can they modify the language's main function to something else without inventing a new c++?

In Microsoft Visual C++ if you choose "Win32 Console Application" you produce a DOS-like applictation that uses the regular "main" function. The "hello world" console application: #include <stdio.h> main() {    printf("Hello, world!\n"; } If you choose "Win32 Application" you will be required to have a WinMain function. The system automatically calls this function for you when your program starts. This application opens a dialog box: #include <windows.h> int WINAPI WinMain(HINSTANCE d1, HINSTANCE d2, LPSTR  d3, int d4) {         MessageBox(NULL, "Hello, World!", "", MB_OK); } This applications open a Window: #include <windows.h> void DrawHello(HWND hwnd) {     HDC hDC;     PAINTSTRUCT paintStruct;     RECT clientRect;     hDC = BeginPaint(hwnd, &paintStruct);     if (hDC != NULL)     {         GetClientRect(hwnd, &clientRect);         DPtoLP(hDC, (LPPOINT)&clientRect, 2);         DrawText(hDC, "Hello, World!", -1, &clientRect,                  DT_CENTER | DT_VCENTER | DT_SINGLELINE);         EndPaint(hwnd, &paintStruct);     } } LRESULT CALLBACK WndProc(HWND hwnd, UINT uMsg,                          WPARAM wParam, LPARAM lParam) {     switch(uMsg)     {         case WM_PAINT:             DrawHello(hwnd);             break;         case WM_DESTROY:             PostQuitMessage(0);             break;         default:             return DefWindowProc(hwnd, uMsg, wParam,  lParam);     }     return 0; } int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,                                         LPSTR d3, int  nCmdShow) {     MSG msg;     HWND hwnd;     WNDCLASS wndClass;     if (hPrevInstance == NULL)     {         memset(&wndClass, 0, sizeof(wndClass));         wndClass.style = CS_HREDRAW | CS_VREDRAW;         wndClass.lpfnWndProc = WndProc;         wndClass.hInstance = hInstance;         wndClass.hCursor = LoadCursor(NULL, IDC_ARROW);         wndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW  + 1);         wndClass.lpszClassName = "HELLO";         if (!RegisterClass(&wndClass)) return FALSE;     }     hwnd = CreateWindow("HELLO", "HELLO",                         WS_OVERLAPPEDWINDOW,                         CW_USEDEFAULT, 0, CW_USEDEFAULT,  0,                         NULL, NULL, hInstance, NULL);     ShowWindow(hwnd, nCmdShow);     UpdateWindow(hwnd);     while (GetMessage(&msg, NULL, 0, 0))         DispatchMessage(&msg);     return msg.wParam; }