That works. I would have thought that the deterministic state of unordered_map might make move-assignment safe, but perhaps not
On Fri, Jan 4, 2019 at 4:33 PM Antoine Pitrou <anto...@python.org> wrote: > > > The move-assigning would definitely not be thread-safe. > > One possibility would be to wrap the std::unordered_map in a > std::shared_ptr, and use the atomic functions for shared_ptr: > https://en.cppreference.com/w/cpp/memory/shared_ptr/atomic > > Regards > > Antoine. > > > Le 04/01/2019 à 23:17, Wes McKinney a écrit : > > hi Gene, > > > > Yes, feel free to submit a PR to fix this. I would suggest populating > > function-local std::unordered_map and then move-assigning it into > > name_to_index_ -- I think this should not have race conditions. If you > > do want to add a mutex, it could be a static one rather than creating > > a new mutex for each StructType > > > > Thanks > > Wes > > > > On Fri, Jan 4, 2019 at 4:10 PM Gene Novark <g...@pdtpartners.com.invalid> > > wrote: > >> > >> These are both effectively-immutable accessors with lazy initialization. > >> However, when accessed from multiple threads a race can occur initializing > >> the name_to_index_ map. This seems like a bug rather than a purposeful > >> design choice based off the cpp/conventions.rst section on Immutability. > >> I'm happy to send a PR if this is agreed to be a bug and what an > >> acceptable fix is (e.g. just eagerly initialize, always use a mutex, > >> last-writer-wins with some sort of atomic ptr, etc.). > >> > >> Thanks, > >> Gene > >> > >> > >> ________________________________ > >> This communication is intended only for the addressee(s), may contain > >> confidential, privileged or proprietary information, and may be protected > >> by US and other laws. Your acceptance of this communication constitutes > >> your agreement to keep confidential all the confidential information > >> contained in this communication, as well as any information derived by you > >> from the confidential information contained in this communication. We do > >> not waive any confidentiality by misdelivery. > >> > >> If you receive this communication in error, any use, dissemination, > >> printing or copying is strictly prohibited; please destroy all electronic > >> and paper copies and notify the sender immediately. Nothing in this email > >> is intended to constitute (1) investment or trading advice or > >> recommendations or any advertisement or (2) a solicitation of an > >> investment in any jurisdiction in which such a solicitation would be > >> unlawful. > >> > >> Please note that PDT Partners, LLC, including its affiliates, reserves the > >> right to intercept, archive, monitor and review all communications to and > >> from its network.
