another try

[PeterPetrik]

another try of API

[abellgithub]

How about something like:

typedef <something opaque> Untwine;

Untwine u;
void untwineStart(&u, InputFiles, OutputSpecification, Options);
void untwineStop(&u);
Feedback untwineStatus(&u);

This would allow untwine to do whatever with the Untwine structure without locking or anything and would also support multiple running instances.

[PeterPetrik]

how would you request cancellation to the running process?

[abellgithub]

call untwineStop()

Are you expecting this to run in a separate process? I assumed that you would create that process or a thread from within your code if that's what you want. Is this incorrect?

[abellgithub]

I've been thinking about this a little more and wondered more about the actual interface. Perhaps this is best done by simply forking a process with a pipe that can be read by the parent. This could all be hidden behind the interface, but then stopping would simply amount to killing the process. Untwine uses PDAL, which isn't really interruptible. I could put code in to stop around the PDAL input and output, but you could still end up with pretty long wait times. I'm not sure what you're expecting.

Also, I'm not sure what to do about progress. There are steps, but it's more likely to be something like a bad MS progress bar where some bits go fast and other bits go slow. Perhaps I could put in some progress info that could be passed through whatever interface we decide, and then later you could figure out how you want to label it (0-100 or whatever).

[PeterPetrik]

• with interface, I am easy with your option too 👍
• re progress: the progress should always increase and has some kind-of regular updates. I am not worried too much that it will not be smooth (expecting MS progress bar experience, but we will not try to predict the remaining time :))
• re interuption: it is OK if you cancel the process on the first possible opportunity. I understand it could be let say after a minute after user action...