[josephg]

> it’s highly unlikely this could be trimmed unless all format strings are parsed at compile time

They probably should be passed at compile time, like how zig does it. It seems so weird to me that in C & C++ something as simple as format strings are handled dynamically.

Clang even parses format strings anyway, to look for mismatched arguments. It just - I suppose - doesn’t do anything with that.

[vlovich123]

That’s passed at compile time via template arguments and/or constexpr/consteval. Even still, there can be all sorts of reasons a compiler isn’t able to omit something as deeply integrated as floating point formatting from a generic floating point library. Rust handles this more elegantly with cargo features so that you could explicitly guarantee you’ve disabled floating point altogether in a generically reusable and intentional way (and whatever other features might take up space).

It’s also important to note that the floating point code only contributed ~44kib out of 75kib but they stopped once the library got down to ~23kib and then removed the c++ runtime completely to shave off another ~10kib.

However, it’s also equally important to remember that these shavings are interesting and completely useless:

1. In a typical codebase this would contribute 0% of overall size and not be important at all

2. A codebase where this would be important and you care about it (ie embedded) is not served well by this library eating up at least 10kib even after significant optimization as that 10kib that is intractible is still too large for this space when you’re working with a max ~128-256kib binary size (or even less sometimes).

[jcelerier]

fmt support full compile-time processing of strings with FMT_COMPILE though: https://fmt.dev/latest/api/#format-string-compilation

[jstimpfle]

The usual case is that libc is linked dynamically so it's not a problem spending a few KB for the library.

And run time format strings are a concise encoding for calling this functionality. I would assume that compile time alternatives take more space.