Flashes the specified window

FlashWindow function

BOOL WINAPI FlashWindow(
  _In_ HWND hWnd,
  _In_ BOOL bInvert
);

FlashWindow in MSDN

demo

//cl tFlashWindow.c && tFlashWindow.exe
int main(int argc, char* argv[]) {
    HWND w = GetConsoleWindow();
    while(TRUE) {
        FlashWindow(w, TRUE);
        Sleep(700);
    }
    return 0;
}

FlashWindowEx function

BOOL WINAPI FlashWindowEx(
  _In_ PFLASHWINFO pfwi
);

FlashWindowEx in MSDN

FLASHWINFO structure