Re: How to set tty settings from perl

Unfortunately after some upgrades, this code now stopped working

That's strange, it doesn't seem like IO::Stty ever supported crtscts.

Does anyone have a suggestion on how to to id properly?

Well, if you look at the source, what the module is doing is mostly tedious, but not too complex. You could set attributes on the port using your own POSIX::Termios object.

You might also be interested in my node Lower-Level Serial Port Access on *NIX; I've been using IO::Termios with good success (also in combination with IO::Stty).

open(Client,"+>/dev/ttyUSB0") || die "open: $!";

BTW, see "open" Best Practices.

My fallback solution is to just system() stty...

Yes, in the worst case that's a possibility, I am guessing this code isn't meant to be super portable anyway. I'd recommend using a module instead of plain system, I showed some examples here.

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Re^2: How to set tty settings from perl by Sec (Monk) on Dec 10, 2019 at 22:48 UTC
Thanks for your suggestion of IO::Termios. Unfortunately it seems that the OS in question (ubuntu) lacks packages for IO::Termios. I may be that crtscts never worked, can't really check right now. But it definitely didn't die while setting 19200, which it now does. Your comment on open is duly noted, but as stated, the code is _OLD_ (written in 2000) and I didn't really plan to rewrite it :-) Lastly, I looked at your link about system -- maybe I'm missing something, but system(LIST) seems to be just fine?	[reply]
Re^3: How to set tty settings from perl by haukex (Archbishop) on Dec 11, 2019 at 18:05 UTC
Unfortunately it seems that the OS in question (ubuntu) lacks packages for IO::Termios. Yes, IO::Termios needs to be installed from CPAN, using e.g. cpanm, although installing modules into the system Perl has the caveats that uninstallation is tricky and it may clash with modules installed using the system's package manager. You could consider local::lib or even perlbrew, and it's also possible to install modules to some other global directory where they won't clash with modules installed by the system package manager (depending on the distro, that could be something like perhaps `/usr/local/lib/site_perl`, check your `perl -V` output for the preconfigured @INC). But it definitely didn't die while setting 19200, which it now does. Yes, that is indeed strange. Can you say what the old and new versions of IO::Stty and Perl were? Lastly, I looked at your link about system -- maybe I'm missing something, but system(LIST) seems to be just fine? Well, on a *NIX system the `system(LIST)` form should be "safe". Using a module gives you the advantage of built-in error handling (e.g. IPC::System::Simple, which has a drop-in replacement for `system`), or the ability to capture `STDOUT`/`ERR` in case you want to hide it from the user or inspect it for error messages (e.g. IPC::Run3). If you don't care about those things, then yes, `system(LIST)` where `LIST` has two or more elements is fine. (BTW, an open mode of `+>` will clobber the file first - for a serial port it's probably fine, but for regular files you would probably want `+<` for read-write access instead.)	[reply] [d/l] [select]
Re^4: How to set tty settings from perl by Sec (Monk) on Dec 18, 2019 at 00:04 UTC
Yea, I don't really want to install perl modules manually. But thanks for the suggestions there, will keep them in mind for the future. I think rt://97576 has analyzed the problem of die()ing, it's just that the changes never got picked up. Point taken on the open() mode. Even though it's probably not relevant, +< seems more logical. Will change that :) Thanks.	[reply]