Here's one more point for a unix-bytestring like behavior: Brandon above mentioned that the ByteString already provides IO routines, which is true. But the reason I went looking for System.Posix.IO.ByteString was that I was writing a named pipes backend for "distributed-process". https://github.com/haskell-distributed/distributed-process This was a pain in the ass because of the tricky blocking / erroring semantics of named pipes and the only way I ended up getting it working was by using the System.Posix.IO "raw system calls", not with any layer above that. But without unix-bytestring I've implemented a pretty silly low performance transport! Cheers, -Ryan It's worth mentioning that the unix-bytestring package grew out of my
attempts at making System.Posix.IO efficient. Before releasing that package I sought inclusion into unix proper, however I was rebuffed because (other than the use of ByteStrings) I kept the same API--- but it turns out that noone liked the original API! Thus, I spun the package off in order to redevelop the API into something nicer; hoping that it would be included in the future.
The issue about using ByteStrings for file names came about in a separate discussion because of some concerns about roundtripping file names on GHC 7.2. Given that the aforementioned unix-bytestring discussion happened on this list and in recent memory, I am *very* disappointed that the new version of unix has decided to steal the namespace that was specifically set aside for unix-bytestring. ~wren