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author | Ricardo Signes <rjbs@cpan.org> | 2013-05-09 09:39:02 -0400 |
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committer | Ricardo Signes <rjbs@cpan.org> | 2013-05-09 09:47:41 -0400 |
commit | d16360cf46a05f65d649c1fe5a38802db2c250d4 (patch) | |
tree | 04e5411bf2ab59e06391a470304d89110200d19e | |
parent | e612b5a06eb8f0fa8371f6ba919f2e4bb370d7db (diff) | |
download | perl-d16360cf46a05f65d649c1fe5a38802db2c250d4.tar.gz |
perldelta: update how we talk about COW
-rw-r--r-- | pod/perldelta.pod | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/pod/perldelta.pod b/pod/perldelta.pod index 4707bf02ea..e0495e6e07 100644 --- a/pod/perldelta.pod +++ b/pod/perldelta.pod @@ -1517,14 +1517,18 @@ or to to avoid compiler warnings with older perls, possibly Perl has a new copy-on-write mechanism that allows any SvPOK scalar to be upgraded to a copy-on-write scalar. A reference count on the string buffer -is stored in the string buffer itself. +is stored in the string buffer itself. This feature is B<not enabled by +default>. -This breaks a few XS modules by allowing copy-on-write scalars to go -through code paths that never encountered them before. +It can be enabled in a perl build by running F<Configure> with +B<-Accflags=-DPERL_NEW_COPY_ON_WRITE>, and we would encourage XS authors +to try their code with such an enabled perl, and provide feedback. +Unfortunately, there is not yet a good guide to updating XS code to cope +with COW. Until such a document is available, consult the perl5-porters +mailing list. -This behaviour can still be disabled by running F<Configure> with -B<-Accflags=-DPERL_NO_COW>. This option will probably be removed in Perl -5.20. +It breaks a few XS modules by allowing copy-on-write scalars to go +through code paths that never encountered them before. =item * |