This is just "hur dur C undefined lol" level of a comment.
If you are serious about your data format supporting round tripping you can and should specify the precise ASCII encoding of binary floats and the inverse. If that means implementations have to ship their own float formatter and parser than so be it - no one is tied to whatever comes with their libc, package manager or no package manager.
But it isn't just about undefined behavior, it's more about the culture of C and how it approaches package management and sharing (or in this case, doesn't). Even if C has Rust level correctness checking it would have the same issue.
>If you are serious about your data format supporting round tripping you can and should specify the precise ASCII encoding of binary floats and the inverse.
Well I guess we have our answer in the case of seriousness. I'm guessing it didn't matter enough for the implementers, or it did matter but could never actually get it implemented. The reasons for this are numerous, contextual (with context we'll never have), and probably not rooted in technical reasoning.
We are talking about the domain of animation and games, after all. Not mission critical code. There's more wiggle room, especially for the complexity of media around when the format was being developed.
If you are serious about your data format supporting round tripping you can and should specify the precise ASCII encoding of binary floats and the inverse. If that means implementations have to ship their own float formatter and parser than so be it - no one is tied to whatever comes with their libc, package manager or no package manager.