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Re: Code fails on perl 5.8.0

by eyepopslikeamosquito (Chancellor)
on Mar 22, 2004 at 01:23 UTC ( #338536=note: print w/replies, xml ) Need Help??

in reply to Code fails on perl 5.8.0
in thread Larry Witticisms from perl Errors

I suspect the root cause of your problem, likely to be seen on Linux/Perl 5.8.0 only, is that the STDOUT file handle is UTF-8 due to your LOCALE settings. I was able to duplicate your problem in that environment. It can be fixed by setting the LANG environment variable, as shown below:

$ perl 1 Oh, waitsRndl.evrm $ env|grep LANG LANG=en_US.UTF-8 $ export LANG=en_US.iso885915 $ perl 1 Oh, wait, that was Randal...nevermind...

Alternatively, adding the following line:

binmode(STDOUT, ":bytes");

to the top of also fixes.

The root cause of this nuisance is described, as follows, in the perl 5.8.1 perldelta.

UTF-8 On Filehandles No Longer Activated By Locale

In Perl 5.8.0 all filehandles, including the standard filehandles, were implicitly set to be in Unicode UTF-8 if the locale settings indicated the use of UTF-8. This feature caused too many problems, so the feature was turned off and redesigned: see Core Enhancements.

UTF-8 no longer default under UTF-8 locales

In Perl 5.8.0 many Unicode features were introduced. One of them was found to be of more nuisance than benefit: the automagic (and silent) ``UTF-8-ification'' of filehandles, including the standard filehandles, if the user's locale settings indicated use of UTF-8.

For example, if you had en_US.UTF-8 as your locale, your STDIN and STDOUT were automatically ``UTF-8'', in other words an implicit binmode(..., ``:utf8'') was made. This meant that trying to print, say, chr(0xff), ended up printing the bytes 0xc3 0xbf. Hardly what you had in mind unless you were aware of this feature of Perl 5.8.0. The problem is that the vast majority of people weren't: for example in RedHat releases 8 and 9 the default locale setting is UTF-8, so all RedHat users got UTF-8 filehandles, whether they wanted it or not. The pain was intensified by the Unicode implementation of Perl 5.8.0 (still) having nasty bugs, especially related to the use of s/// and tr///. (Bugs that have been fixed in 5.8.1)

Therefore a decision was made to backtrack the feature and change it from implicit silent default to explicit conscious option. The new Perl command line option -C and its counterpart environment variable PERL_UNICODE can now be used to control how Perl and Unicode interact at interfaces like I/O and for example the command line arguments. See -C in the perlrun manpage and PERL_UNICODE in the perlrun manpage for more information.

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