Shlomi Fish <shlo...@shlomifish.org> writes:
> On Sun, 14 May 2017 12:08:59 +0300
> Shlomi Fish <shlo...@shlomifish.org> wrote:
>
>> Hi lee,
>>
>> On Sat, 06 May 2017 02:06:19 +0100
>> lee <l...@yagibdah.de> wrote:
>>
>> > Hi,
>> >
>> > how can a sleeping program react to a key that was pressed without
>> > return being pressed?
>> >
>> >
>> > perl -e 'use Term::ReadKey; my $ke = ReadKey(10); print "k: $ke\n";'
>> >
>> >
>> > ... shows that:
>> >
>> >
>> > + ReadKey() returns undef after the timeout
>> >
>> > + ReadKey() returns undef after the timeout even when you pressed keys
>> >
>> > + ReadKEy() returns the first key of those that were pressed before the
>> > timeout expires when you hit return before it does
>> >
>> >
>> > So you always have to hit return :(
>> >
>> > I'm finding that entirely useless for instances in which a program is
>> > sleeping for some time (let's say 10 minutes) but supposed to do
>> > something immediately when a key is pressed, and without pressing
>> > return. For example, I might want to press 'q' to quit and don't want
>> > to wait 10 minutes for the program to react, and of course, I don't want
>> > to press enter.
>> >
>> > How can that be done?
>> >
>> >
>>
>> This program from perldoc Term::ReadKey is working as advertised:
>>
>> «
>> #!/usr/bin/perl
>>
>> use strict;
>> use warnings;
>>
>> use Term::ReadKey;
>> ReadMode 4; # Turn off controls keys
>> my $key;
>> while (not defined ($key = ReadKey(-1))) {
>> # No key yet
>> }
>> print "Get key $key\n";
>> ReadMode 0; # Reset tty mode before exiting
>>
>> »
>>
>> Note that it may be a busy loop. It mad be a bug in Term::ReadKey or you're
>> doing something wrong.
>>
Such a loop is what I'm trying to avoid. It would probably keep a CPU
busy 100% doing basically nothing.
> I've now tried this program and it seems to do what you want:
>
> perl -e 'use Term::ReadKey; ReadMode 4; my $ke = ReadKey(3); print "k: $ke\n";
> ReadMode 0;'
Thanks, that seems to work :)
> The key (pardon the pun) is adding the ReadMode calls.
Indeed --- I didn't change the ReadMode because I didn't see any need to
disable control keys. Without changing the ReadMode, I have to press
Enter.
--
"Didn't work" is an error.
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