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sccn / liblsl

C++ lsl library for multi-modal time-synched data transmission over the local network
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Remove last remains of Boost.Mutex #148

Closed tstenner closed 2 years ago

tstenner commented 2 years ago

shared_mutex in the inlet connection is the last remainder of Boost.Mutex, as it first appears in the C++17 stdlib.

This PR falls back to a plain mutex / unique_lock instead of shared_lock for C++11 builds and removes the rest of Boost.Mutex and its dependencies (564 files, 118626 lines).

Using a unique_lock to protect the host_info gives a tiny speedup when the lock isn't held be another thread but blocks while another thread copies data from the host info. In practice, it's not noticable as accesses to the host_info are rare and not in a hot path; additionally the time the mutex is held in the endpoint resolution has been reduced to the absolute minimum (1f41390).

Special care has been taken to ensure that no code path relies on multiple readers holding a shared_lock or blocks indefinitely during stream recovery (many thanks to @cboulay for going through every mutex usage individually and critical feedback!).

cboulay commented 2 years ago

As Tristan said, I looked over this quite carefully (except for the Boost excision parts) and I didn't identify any problems. @tstenner , if no one else interjects (e.g., with a request for more time) before Monday then IMO you are free to merge.