Reckless is an extremely low-latency, high-throughput logging library. It was created to perform extensive diagnostic logging without worrying about performance. Other logging libraries boast the ability to throw log messages away very quickly. Reckless boasts the ability to keep them all, without worrying about the performance impact. Filtering can and should wait until you want to read the log, or need to clean up disk space. The code generated at the call site consists of: - Pushing the arguments on a thread-local queue. This has the same cost as pushing the arguments on the stack for a normal function call. - Call to Boost.Lockless (NB: this is bundled with the library, not an external dependency) to register the write request on a shared lockless queue. The actual message formatting and writing is performed asynchronously by a separate thread.