On Fri, 03 Nov 2017 15:12:15 -0500
"Martin McCormick" <marti...@suddenlink.net> wrote:
> What is needed, however, is to be able to use the are_match
> feature which fills a buffer with data until a pattern is
> detected which stops the read and gives you a series of bytes
> that may not necessarily end with a newline or carriage return.
>
> I have never yet gotten anything like the following to
> work:
>
> #!/usr/bin/perl -w
> use strict;
> #use warnings::unused;
> use File::Basename;
> use File::Copy;
> use File::Spec;
> use Time::Local;
> use Device::SerialPort;
>
> sub comm { #serialport
>
> my $dev = "/dev/ttyS0";
> my $c = "";
> my $port = Device::SerialPort->new("$dev");
> $port->baudrate(9600); $port->databits(8); $port->parity("none");
> $port->stopbits(1); $port->handshake("none");
> $port->write_settings;
>
> until ("" ne $c) {
> my $c= $port->lookfor;
> print ("$c\n") if $c;
> }
> return;
> } #serial port
[...]
> I have tried it with and without an are_match pattern and
> it just roars along, looping endlessly at the lookfor statement
> and never picking up anything.
Instead of assigning the result of $port->lookfor to $c, you've created
a new lexically-scoped $c (with "my $c") which exists only within that
loop body execution - after the execution, it goes away, and the $c the
loop is looking for, at a higher scope, will still be empty.
I imagine things might change if you remove the "my" from that
assignment, so that you're assigning the result to the $c that the loop
condition is looking at.
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