http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30162
--- Comment #49 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2013-02-18 21:46:58 UTC --- Here's a proof of concept patch which lets the test cases "work" due to buffering. Index: unix.c =================================================================== --- unix.c (Revision 195922) +++ unix.c (Arbeitskopie) @@ -995,7 +995,8 @@ s->file_length = statbuf.st_size; /* Only use buffered IO for regular files. */ - if (S_ISREG (statbuf.st_mode) + if ((S_ISREG (statbuf.st_mode) + || S_ISFIFO (statbuf.st_mode)) && !options.all_unbuffered && !(options.unbuffered_preconnected && (s->fd == STDIN_FILENO What it doesn't do is handle writes larger than BUFSIZE, and this limitation is not communicated up from the stream library to the record length, and also not the other way. This would break the abstraction (but maybe we would not care, would we?)