According to the documentation I/O Streams defines blocking I/O as: http://www.boost.org/libs/iostreams/doc/concepts/blocking.html
A Device is Blocking if a read request never produces fewer characters than requested except at end-of-stream, and if a write request never consumes fewer characters than requested under any circumstances.
So, if I issue an iostream::read() with 10 characters, and only 5 come back, this is considered non-blocking. To me, this is inconsistent with at least Unix read() semantics. As long as iostream::read() blocks for at least 1 character, it should be considered blocking, no? I don't have a copy of the C++ standard handy, but my Stroustrup book just says that iostream::read(Ch *p, streamsize n) "returns at most n char". Thus it heavily implies that reading less than "n char" is not only possible, but not an error or exceptional condition. But the book really doesn't say anything more than that. I am just curious because I am looking into using Boost Iostreams as a wrapper around some socket I/O that uses standard Unix read() semantics. I don't use the socket in non-blocking mode, but since the Unix read() may return less than "n char", do I need to write a loop that ensures exactly "n char" is read, unless an EOF occurs? Thanks, -Dave