Programmatically press a button on another application (C, Windows)

Question

I\'m trying to use the following code to press a button on my other application:

HWND ButtonHandle;
if( (wnd = FindWindow(0, \"Do you want to save?\")) )
{   
           


        

Answer 1

SendMessage(btnHandle, WM_LBUTTONDOWN, 0, 0);
SendMessage(btnHandle, WM_LBUTTONUP, 0, 0);
SendMessage(btnHandle, WM_LBUTTONDOWN, 0, 0);
SendMessage(btnHandle, WM_LBUTTONUP, 0, 0);

You have to send a button click twice. Not sure why (maybe the first click only activates the window of the button), but I'm using this code for a long time and it always worked for me.