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Re: Termios and waiting for character input


Gary Thomas wrote:
Jonathan Larmour wrote:
Gary Thomas wrote:
Jonathan Larmour wrote:
Non-canonical mode processing was only implemented to support VMIN=0,TIME=0. Support for VMIN>0 is rudimentary and I wouldn't trust it. But VMIN defaults to 0, and that sample code posted doesn't attempt to set it to anything else.

I imagine it defaults to something else on Linux, hence the difference in behaviour. <fx: goes and checks> Aha, in fact it defaults to 6. The POSIX standard does not set any requirements for the default value, so eCos is fine on this count.

Thanks for looking into this.


Perhaps we should make the default values for VMIN/VMAX configurable,
possibly with settings that match other systems?

Maybe so if I had more confidence it worked! If Andre-John (or yourself) can play around with VMIN>0 and don't find any problems, then we could change the default for VMIN. NB there is no VMAX, but if you meant TIME, then TIME>0 is definitely unsupported in the current code.

It does work correctly (or at least the same as Linux) when VMIN=1.
If I set VMIN=6, then I have to type 6 characters before the first one is seen.
Perhaps that's where a setting of TIME>0 would matter...

Yes indeed, that's the correct behaviour for TIME=0. So maybe it does work, and we could set default VMIN to 1.


At least we could have a way to default the value of VMIN and document
the fact that TIME>0 is not implemented (if not already in the docs)

Since VMIN can be set in a well-known and standard way at run-time, I'm not sure there's much value in a configuration option for the default.


Termios is unfortunately undocumented. This was in the days when making doc edits happen was like pulling teeth. And it became one of those things that just never happened.

Jifl
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