Thanks John,

I noticed that also WindowFromPoint is using POINT so i made external as per below:

Function longlong WindowFromPoint(REF POINT lpPoint) library "User32.dll"

But its returning 0 , with regards to point coordinates that Externs.GetCursorPos(lpPoint) is returning in pixel or PBU. below is the point structure:

global type point from structure
    long        X
    long        Y
end type

Regards,

Mayller

Your external function declaration for the WindowFromPoint API function should not include the keyword "REF", as this causes the 8-byte memory address of the POINT structure to be passed as the argument value instead of passing the 8-byte POINT structure by value, as the API definition states (computers insist on doing exactly what you tell them to do, darn it ). See if that helps.

I'm attaching a zip file containing exported source for two objects: Structure s_point and Window w_main.

Normally I would've attached a pbl, but because you are using PB 12.6 and since I have no version that old, I exported the source from a later version of PB.

This is a very small, simple, single-window you can easily add to a new test app. The window utilizes the GetCursorPos, WindowFromPoint and GetWindowTextW API functions. It works from PB 2019 R2's IDE, as well as from a compiled 32-bit exe and a compiled 64-bit exe. There is nothing in either object that should preclude these two objects from importing into PB 12.6. But, if there is a problem, you can edit the w_main.srw source file and copy/paste the small amount of code it contains.

With the app running, as you move the cursor around over the app and over other apps and the Windows desktop, task bar, etc. the app will display the screen coordinates of the cursor's position, the Windows handle of the window/control that the cursor is over, and when possible it displays the title/text of the window/control the cursor is over.

I was VERY surprised that when I initially coded the WindowFromPoint external function declaration to pass a point structure to the WindowFromPoint API function, PB produced an error at runtime concerning a problem with the execution call stack - indicating that passing a point structure was NOT the proper way to invoke this API function... in spite of what Microsoft's online documentation states. So, I passed in the X & Y coordinates as PB Long's (exactly as you had initially had it), and it works. In both 32-bit and 64-bit. Not sure why it needs to be this way.

Create a new workspace, create an Application target & pbl & application object, then import the s_point structure, then import the w_main window. Open(w_main) from the application's Open event and it should run from within the IDE. I created a PB Project object to produce a 32-bit exe and another to produce a 64-bit exe. Both work.

If I were to venture a guess, the issue you're experiencing is somehow related to your handling of window handles.

I hope this helps you out.

Regards, John