Working on DB's files, which are numerous and for which the processing is complicated, I found I really wanted to be able to cancel a batch operation, so I've repurposed the Progress form I wrote for Markin 4 to show how the batch is going, and enable the user to press a Cancel button and stop the process. This is a great improvement for large batches. The cancel flag is checked at the end of each replace or script operation, so as long as those operations are completing in good order, it's pretty snappy.

The problem of how to monitor and abort a frozen or looping script operation while it's happening still remains, though. I've been doing a lot more thinking and reading about this, and it seems likely that only something fairly aggressive such as TerminateProcess could do it. The script code would all have to run as a separate thread, and there would have to be a monitor thread with a timer, which was initiated when the process began, and which gave the user the option to kill a script process after a timeout had been reached without the thread terminating. That code could also check for the Cancelled flag, and kill a process when that was True but the process had been running for a (perhaps shorter) timeout. It'll take some work to get this implemented and tested. I'm still not sure there's a clean way to kill a process running in a C++ dll from Delphi without orphaning some resources.