Henry Vermaak wrote:
On 09/03/11 11:30, Mark Morgan Lloyd wrote:
Henry Vermaak wrote:
On 08/03/11 10:30, Mark Morgan Lloyd wrote:
Can anybody say whether there is a good reason that serial.pp lacks a
function to read the CD signal?
Is SerFlush, which calls fpfsync, intended to discard input data,
output
data or both?
fsync just makes sure all the in-kernel caches are written to the
device. Flushing input data is just a matter of reading it.
Thanks for that Henry. Obviously there's scope for confusion here with
the kernel's tcflush() and tcdrain() functions, where tcflush discards
input and/or output data.
You're right. Thinking about it, I don't know what the use of an fsync
is in SerFlush, since you still don't know if it's been transmitted. I'd
consider this a bug, SerFlush should use tcdrain.
I was using this to communicate with an HP instrument a few weeks ago,
so have my own re-implementation of some of the stuff. I'll look at
doing a patch, preparatory to seeing if I can hack a complementary
Win-32 equivalent.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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