4 ms·

Doesn't fwrite more or less write directly to the FILE buffer, if buffering is enabled? I'm curious to take a closer look at fmtlib/fmt, which APIs treat FILE

Doesn't fwrite more or less write directly to the FILE buffer, if buffering is enabled? I'm curious to take a closer look at fmtlib/fmt, which APIs treat FILE as non-opaque? Edit: ah, found some of the magic, I think: https://github.com/fmtlib/fmt/blob/35dcc58263d6b55419a5932bd6b0b3029a0a8c00/include/fmt/format-inl.h#L1513-L1557 https://github.com/fmtlib/fmt/blob/35dcc58263d6b55419a5932bd... I'm curious how much speedup is gained from this.

vitaut 1y ago
With fwrite that would be another level of buffering in addition to FILE's buffer. If you are interested in what {fmt} is doing, a good starting point is https://github.com/fmtlib/fmt/blob/35dcc58263d6b55419a5932bd6b0b3029a0a8c00/include/fmt/format-inl.h#L1514 https://github.com/fmtlib/fmt/blob/35dcc58263d6b55419a5932bd.... It is also possible to bypass stdio completely and get even faster output (https://vitaut.net/posts/2020/optimal-file-buffer-size/ https://vitaut.net/posts/2020/optimal-file-buffer-size/) and while it is great for files, it may introduce interleaving problems with things like stdout.