This Week on perl5-porters (27 January / 2 February 2003)

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This Week on perl5-porters (27 January / 2 February 2003)

Hi all, here's your weekly dose of bug and fixes. Fold constants, send signals, leak memory and introspect layers through this week's summary.

Constant folding in conditionals

The ?: conditional operator is optimized away by perl when the condition is constant. This leads to a strange behavior, reported as bug #20444 by Ton Hospel : the following construct

    $_ = "foo"; print "foo" =~ (1 ? /foo/ : /bar/);

prints 1, because it's internally equivalent to :

    $_ = "foo"; print "foo" =~ /foo/;

But in fact it should print nothing, as it should be equivalent to

    $_ = "foo"; print "foo" =~ 1;

(this 1 being the value of /foo/, once evaluated.)

(of course, the proper way to mix regexps and ?: is to use qr//.)

    http://archive.develooper.com/perl5-porters@perl.org/msg91125.html

Signal handler configuration mess

Shevek reports (bug #20491) that assigning to $SIG{RTMIN} results in a segfault on his linux system. After having inspecting his configuration, it appears that Configure has assigned the signal number -1 to SIGRTMIN. Why, we don't know (yet).

    http://archive.develooper.com/perl5-porters@perl.org/msg91194.html

Minor leak

Bill Bennett spotted a minor memory leak in the freeing of subroutines. Dave Mitchell found that one in every 64K ops will not be freed, due to a hack used by the B::C compiler backend, and Paul Johnson provided a patch.

    http://archive.develooper.com/perl5-porters@perl.org/msg91265.html

gcc locale-dependent messages

The makedepend script (that calculates dependencies between source files) is fooled by gcc 3.2.1, when run under a french locale (and probably other non-english locales as well). That's because makedepend relies on the output of gcc to do its job. Nicholas Clark thinks that gcc generating programmatic output (not human output) that varies depending on locale is a bug in gcc, and should be reported as such. H.Merijn Brand proposes to use weaker patterns to match gcc output. Rafael Garcia-Suarez proposes also to force the C locale in makedepend.

    http://archive.develooper.com/perl5-porters@perl.org/msg91453.html

Run-time access to ${^OPEN} values

Autrijus Tang wanted a way to know what default PerlIO layers are used by a given block of Perl code. He proposed a patch to open.pm to store this information on a package per package basis. But as the open pragma is lexically scoped, this approach wasn't sufficient. Rafael pointed out that it's available from the op tree and provided a naive C implementation, which was quickly turned into a module, Devel::Hints, by Autrijus.

Nick Ing-Simmons suggested that this runtime access to ${^OPEN} values could be implemented in XS in the core, to be available in the open:: namespace.

    http://archive.develooper.com/perl5-porters@perl.org/msg91423.html
    http://search.cpan.org/author/AUTRIJUS/Devel-Hints/

In brief

John Peacock released version.pm v0.28, that now includes a subclass, version::AlphaBeta, which demonstrates using alphanumeric version strings, instead of strict numeric versions.

Jarkko Hietaniemi hopes someone will write the documents README.linux and README.macosx. (We have already 37 README documents, that provide notes and installation instructions specific to various platforms, but those two popular OSes lack documentation.) John Adams volunteered for OSX.

Rafael suggests to remove the obsolescent -u command-line switch. Ton Hospel says that it could be reused as "the Unicode switch", but Jarkko objects that this could create strange problems when different versions of perl are used.

Stephane Payrard notices that IO::Handle can't be used together with Inline::Files, at least on perl 5.8.0. The origin of the problem is unknown (but patches are welcome).

Jarkko released a snapshot of the maintenance branch of perl 5.8.

About this summary

This summary was brought to you, as usual, by Rafael Garcia-Suarez. Summaries are available on http://use.perl.org/ and/or via a mailing list, which subscription address is perl5-summary-subscribe@perl.org. Comments, corrections and additions are welcome.