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Hello, wise ones,

I'm using Perl under an UTF-8 Linux environment (LC_ALL='en_US.UTF-8'), with a perl script which is in an UTF-8-encoded file.

This script states "use utf8;" on one of its first lines, and then, I have some scalar definitions which use accentuated characters (I'm French, so there are some '', '', '', '', '', etc.)

However, when I print strings defined in the script, I see they are garbled (the accentuated characters come out as ugly white squares on the black background of my Putty terminal - Which is ALSO configured to use UTF-8)

Now, if I write :
binmode STDOUT, ':encoding(UTF-8)';
and do the same for STDERR, I get no more garbled characters, they all come out cleanly.

My question is: Why do I have to specify this encoding ? I thought that Perl adapted to its environment, and the localization environment variables should all be readable, right ?

Can someone explain the reason to me, or point me to relevant documentation ?

Thanks in anticipation.


EDIT: Ok, so, after reading through all these fine answers, I think I understand better my problems, and the solutions:

  • I had probably tried a Perl version which DID take upon itself to automatically convert some streams, but not some others, and that had left me confused
  • I'm pretty sure, by now, that Perl "decodes" input from Latin-1, and "encodes" output to Latin-1, by default.
  • I've discovered a fine command-line switch, '-C' (you may read about it in the 'perlrun' documentation), which does exactly what I would have expected Perl to do, if called with the parameter 'L'. That is, '-CL' should decode STDIN from UTF-8, or encode STDOUT / STDERR to UTF-8, if such an encoding is mentioned in the 'LC_ALL', 'LC_TYPE', or 'LANG' environment variables.
  • Of course, using explicit encoding (or explicitly stating in the script that we want it autodetected) is best practice, even if a bit more cumbersome to write

Please feel free to correct me if you feel that my conclusions are false or misleading.


In reply to Default encoding rules leave me puzzled... by kzwix

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