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raymanfx / libv4l-rs

Video4Linux2 bindings for Rust
MIT License
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`stream.next()` blocks when camera unplugged #16

Closed EtomicBomb closed 2 years ago

EtomicBomb commented 3 years ago

When I start a stream and unplug the camera, the stream.next() call blocks forever. It would be nice if I could set a timeout. Perhaps I'm missing something, but I can't see a way to do that in this library. It seems like there's a poll function that's made for this. Perhaps this should be the standard behavior - I think most users would expect an error when a camera is unplugged.

raymanfx commented 3 years ago

I'm going to test this later. Returning an error (or None in the case of next() should definitely be the default behavior.

raymanfx commented 3 years ago

Okay, I was able to reproduce this. Do you want to work on a PR that adds something like a set_timeout(..) and a poll(..) method to the two stream implementations in src/io/{mmap, userptr}/stream.rs?

The next() method should then perform the polling and return None in case of timeout I think. I'm going to merge the next branch into master today or tomorrow, so I'd advise to start on top of that branch instead of the current master.

spebern commented 2 years ago

I had the same problem when using: https://github.com/loyd/rscam

With the changes here https://github.com/loyd/rscam/pull/32/files timeout can be added and also the pselect will return an error when the camera is unplugged.