Seqlock

A single/multi-writer multi-reader Sequential Lock implemented in C++23, with an accompanying Go wrapper. Only supports ARM64 and X86-64. Has optional support for multiple writers through a spinlock.

Getting started

Start with examples/. Main code is in seqlock/include/seqlock.

Building the C++ part

• Install nix.
• Invoke nix-shell.
• Run ./setup.sh.
• Build with cmake -GNinja -S . -B build; cmake --build build;.
• Run tests with ./build/tests/run.
• Build the release version with cmake -GNinja -DCMAKE_BUILD_TYPE=Release -S . -B build_rel.
• The static library will be in build/seqlock/libseqlock.a. You can install everything with ninja install while in build/.
• Check examples/ and the files ending with .test.cpp and .bm.cpp.
• Benchmarks are build/*.bm. Make sure they're release targets before running them, as shown above.

Go bindings

The module's path is github.com/sergiu128/seqlock.cpp/bindings-go/seqlock. See bindings-go/examples/main.go on how to use it. libseqlock.a (release target) and ffi.h are copied on each new release from the cpp part.

Credits

I found out about seqlocks from David Gross' talk on C++ in trading. This project adds the right memory barriers on top of his implementation and provides a broader API while also adding support for multiple writers.