Next generation Unix pipe by Alex Larsson

Re:Next generation Unix pipe by Alex Larsson by rogerbinns on Saturday August 11, 2012 @04:38PM (#4370931)

That requires the first byte sent be compatible with whatever format is ultimately used. As an example for ps, the first byte in JSON should be a { while for plain text it should be space. (We get a little lucky since a space would also be acceptable for JSON, but I doubt there is a universal first byte.) And an initial space isn't accept for a programs like find or grep in either text or null separation mode.

I don't want to belittle what you've done, but the point remains. This can't be done robustly without an additional system call. What you have is tantalizingly close. Even a call as simple as telling the sender that the receiver has called read() would complete your solution.

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Re:Next generation Unix pipe by Alex Larsson by alexlarsson on Sunday August 12, 2012 @03:40AM (#4372113)

Not really. All you need to be able to do is to produce the first byte of whatever would have been produced in the "fallback case", i.e. when the reader does not handle format negotiation. Then, when the writer sees that the reader supports format negotiation it will need to signal that the alternative format was chosen. I do this by sending a zero byte (which should never appear in the fallback text format). Then the two first bytes are skipped as part of the negotiation framework when a non-fallback format was chosen.

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