quoth Elliot Robinson
As a platform-specific optimization, this makes total sense. Most of the people who need this optimization know they need it. My fear is that offering "handles are for buffered I/O" (and statements like it) as general case rules leads to the "I'm new to <field> and I'm using System.Posix.IO for unbuffered IO because Handles aren't good for that, and now my program doesn't compile on <non-Posix OS>" ilk of Haskell-Cafe/SO questions.
Your fears are misplaced. No one is going to do that, ever. Please bear in mind that we're talking about a Posix Fd produced by another Posix terminal function. That is where you will see one programmer after another feed this Fd into a Handle, under the mistaken impression that it's the only legit way to do I/O on it in Haskell, and then have various problems that we're talking about. When it's for buffered I/O, then it makes sense, otherwise it's probably an error. To address J.K.'s (lest I misspell) probably ironic question seriously, why I certainly say Haskell should strive to be as compatible as possible with ANSI C, whatever Mr. Allbery may think. Gratuitous difference in functionality that's clearly based on C I/O would benefit no one. Donn