@slembcke writing FFTs that are actually fast is a real art form. I wrote the FFT library I use in my projects about a decade ago and tweaked it to get it fast on NEON and amd64. Heaps of fun.

@funkylab But yeah, the more I figure out, the more it seems like the answer to every edge case is: “whatever the easiest thing would be to implement is the answer”

@funkylab I agree with you about the semantics around if directives in this particular example. The unclear part is the definition of what “#pragma once” actually does. You could argue that in the second processing of the file, when it sees the pragma, it knows that the file is already being processed lower in the file stack. So you could reason: maybe it should abort the processing and assume the file had been processed.

@rygorous blocks contain frames of samples except when the frames are actually blocks of samples or when samples are actually frames.