Messages in this thread | | | From | "Michael Kerrisk (man-pages)" <> | Date | Fri, 21 Mar 2014 16:41:11 +0100 | Subject | Re: man termios |
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>> Peter, do you agree that Linux appears to differ from POSIX here? (Not >> sure if you tried my test program to verify...) > > > I did run the test program to validate that it's observed behavior is that > implemented by Linux, with which I'm very familiar. > I don't have a test setup for other *nixes. > > I would be interested to know the results of > > ./noncanonical 0 5 3 0 > hello
Solaris 10: read() completes when 5 bytes received. OpenBSD 5.4 read() completes when 5 bytes received.
> and > > ./noncanonical 0 5 3 2 > hel
Solaris read blocks() OpenBSD read blocks
Plus my test case where Linux differs:
./noncanonical 100 5 3 0
Linux: read() returns after 3 bytes input
Solaris: read() returns only after 5 bytes input OpenBSD: read() returns only after 5 bytes input
> on other platforms. > > With respect to POSIX compliance, it's hard to say. I'm not sure the > spec contemplates the degenerate case where max bytes < MIN. And
Well, given the way the other implementations behave, I think it does contemplate it, because it carefull avoids talking about the number of bytes requested by read() in that case.
> specifically > with regard to terminal i/o behavior, POSIX is essentially ex post facto, > and is really documenting existing behavior. > > Other than the degenerate case of max bytes < MIN, is there any other > variation between Solaris and Linux in non-canonical mode?
The only one I've seen is the one I noted. I haven't tested too exhaustively though.
Cheers,
Michael
-- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
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