Remove duplicate assignment to PL_eval_root in Perl_create_eval_scope

[p5sagit/p5-mst-13.2.git] / pod / perlxs.pod

diff --git a/pod/perlxs.pod b/pod/perlxs.pod
index b3ba08f..6d14bae 100644 (file)
--- a/pod/perlxs.pod
+++ b/pod/perlxs.pod
@@ -1926,7 +1926,6 @@ Below is an example module that makes use of the macros.
        CODE:
        MY_CXT_CLONE;
 
-
 B<REFERENCE>
 
 =over 5
@@ -2013,8 +2012,36 @@ my_cxt_t structure. Calling C<MY_CXT_CLONE> (typically via the package's
 C<CLONE()> function), causes a byte-for-byte copy of the structure to be
 taken, and any future dMY_CXT will cause the copy to be accessed instead.
 
+=item MY_CXT_INIT_INTERP(my_perl)
+
+=item dMY_CXT_INTERP(my_perl)
+
+These are versions of the macros which take an explicit interpreter as an
+argument.
+
 =back
 
+Note that these macros will only work together within the I<same> source
+file; that is, a dMY_CTX in one source file will access a different structure
+than a dMY_CTX in another source file.
+
+=head2 Thread-aware system interfaces
+
+Starting from Perl 5.8, in C/C++ level Perl knows how to wrap
+system/library interfaces that have thread-aware versions
+(e.g. getpwent_r()) into frontend macros (e.g. getpwent()) that
+correctly handle the multithreaded interaction with the Perl
+interpreter.  This will happen transparently, the only thing
+you need to do is to instantiate a Perl interpreter.
+
+This wrapping happens always when compiling Perl core source
+(PERL_CORE is defined) or the Perl core extensions (PERL_EXT is
+defined).  When compiling XS code outside of Perl core the wrapping
+does not take place.  Note, however, that intermixing the _r-forms
+(as Perl compiled for multithreaded operation will do) and the _r-less
+forms is neither well-defined (inconsistent results, data corruption,
+or even crashes become more likely), nor is it very portable.
+
 =head1 EXAMPLES
 
 File C<RPC.xs>: Interface to some ONC+ RPC bind library functions.