What this error means and how to fix it? `Constructing a IO::Async::Stream with an encoding-enabled-CodePudding

When I do:

use IO::Async::Stream;
$tty =  IO::Async::Stream->new(
    read_handle  =>  \*STDIN,
    write_handle =>  \*STDOUT,
    on_read      =>  \&tty_read,
);

I get error: Constructing a IO::Async::Stream with an encoding-enabled handle may not read correctly

On other host same code works fine.

Why on this host I get this error and how to fix it?

CodePudding user response：

Ok. This is different host and only environment could differ. So I did:

# env | grep PERL
PERL_UNICODE=SA
PERL5LIB=/usr/local/proj/lib:/usr/local/proj/local/lib/perl5:

Then I did $ unset PERL_UNICODE and my script works fine now.

See documentation here about PERL_UNICODE

CodePudding user response：

It appears that IO::Async::Stream expects a "raw" file handle, but you are providing one with an encoding layer attached.

you might by using the following:

use open ':std', ':encoding(UTF-8)';

If so, replace it with the following:

use open ':encoding(UTF-8)';
BEGIN { 
   binmode( STDERR, ':encoding(UTF-8)' );
}

To deal with decoded text, you'll also need to decode or encode the data received from and passed to $tty, say by using the encoding constructor parameter. You can't simply pass the text received by on_read to decode as it might contain a partial character.