On Fri 12 Jan 2018 11:15, l...@gnu.org (Ludovic Courtès) writes: > Andy Wingo <wi...@igalia.com> skribis: > >> On Thu 11 Jan 2018 22:55, Mark H Weaver <m...@netris.org> writes: > > [...] > >>>>> Out of curiosity, is there a reason why you're using an unbuffered port >>>>> in your use case? >>>> >>>> It’s to implement redirect à la socat: >>>> >>>> >>>> https://git.savannah.gnu.org/cgit/guix.git/commit/?id=17af5d51de7c40756a4a39d336f81681de2ba447 >>> >>> Why is an unbuffered port being used here? Can we change it to a >>> buffered port? >> >> This was also a question I had! If you make it a buffered port at 4096 >> bytes (for example), then get-bytevector-some works exactly like you >> want it to, no? > > It might work, but that’s more by chance no?
No, it is reliable. get-bytevector-some on a buffered port must either return all the buffered bytes or perform exactly one read (up to the buffer size) and either return those bytes or EOF. As far as I understand, that is exactly what you want. Using buffered ports has two additional advantages: you get to specify the read size, and returned bytevectors can be allocated to precisely the right size (no need to overallocate then truncate). Andy