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| author | David Mitchell <davem@iabyn.com> | 2013-04-24 16:29:42 +0100 |
|---|---|---|
| committer | David Mitchell <davem@iabyn.com> | 2013-04-24 16:40:15 +0100 |
| commit | a453e28ae209e82ef2533e2e2bfe25490fd60654 (patch) | |
| tree | 09fa23d3eb05b5f03e5b0c09b936b0ec5389ce26 /pod/perlsub.pod | |
| parent | 5fbe83117ea59ccad42477c465113c7550a3675d (diff) | |
| download | perl-a453e28ae209e82ef2533e2e2bfe25490fd60654.tar.gz | |
make qr/(?{ __SUB__ })/ safe
(See RT #113928)
Formerly, __SUB__ within a code block within a qr// returned
a pointer to the "hidden" anon CV that implements the qr// closure. Since
this was never designed to be called directly, it would SEGV if you tried.
The easiest way to make this safe is to skip any CXt_SUB frames that
are marked as CXp_SUB_RE: i.e. skip any subs that are there just to
execute code blocks. For a qr//, this means that we return the sub which
the pattern match is embedded in.
Also, document the behaviour of __SUB__ within code blocks as being
subject to change. It could be argued for example that in these cases it
should return undef. But with the 5.18.0 release a month or two away, just
make it safe for now, and revisit the semantics later if necessary.
Diffstat (limited to 'pod/perlsub.pod')
| -rw-r--r-- | pod/perlsub.pod | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/pod/perlsub.pod b/pod/perlsub.pod index 87d45d30ac..027d7bea36 100644 --- a/pod/perlsub.pod +++ b/pod/perlsub.pod @@ -232,6 +232,9 @@ your subroutine's name. return($x * __SUB__->( $x - 1 ) ); }; +The behaviour of C<__SUB__> within a regex code block (such as C</(?{...})/>) +is subject to change. + Subroutines whose names are in all upper case are reserved to the Perl core, as are modules whose names are in all lower case. A subroutine in all capitals is a loosely-held convention meaning it will be called |