C<AvARRAY> points to the first element in the array that is visible from
Perl, C<AvALLOC> points to the real start of the C array. These are
usually the same, but a C<shift> operation can be carried out by
-increasing C<AvARRAY> by one and decreasing C<AvFILL> and C<AvLEN>.
+increasing C<AvARRAY> by one and decreasing C<AvFILL> and C<AvMAX>.
Again, the location of the real start of the C array only comes into
play when freeing the array. See C<av_shift> in F<av.c>.
If you are not sure then doing an C<SvREFCNT_inc> and C<sv_2mortal>, or
making a C<sv_mortalcopy> is safer.
-The mortal routines are not just for SVs -- AVs and HVs can be
+The mortal routines are not just for SVs; AVs and HVs can be
made mortal by passing their address (type-casted to C<SV*>) to the
C<sv_2mortal> or C<sv_mortalcopy> routines.
e PERL_MAGIC_envelem vtbl_envelem %ENV hash element
f PERL_MAGIC_fm vtbl_fm Formline ('compiled' format)
g PERL_MAGIC_regex_global vtbl_mglob m//g target / study()ed string
- H PERL_MAGIC_hints vtbl_sig %^H hash
+ H PERL_MAGIC_hints vtbl_hints %^H hash
h PERL_MAGIC_hintselem vtbl_hintselem %^H hash element
I PERL_MAGIC_isa vtbl_isa @ISA array
i PERL_MAGIC_isaelem vtbl_isaelem @ISA array element
=head2 Scratchpads
The question remains on when the SVs which are I<target>s for opcodes
-are created. The answer is that they are created when the current unit --
-a subroutine or a file (for opcodes for statements outside of
-subroutines) -- is compiled. During this time a special anonymous Perl
-array is created, which is called a scratchpad for the current
-unit.
+are created. The answer is that they are created when the current
+unit--a subroutine or a file (for opcodes for statements outside of
+subroutines)--is compiled. During this time a special anonymous Perl
+array is created, which is called a scratchpad for the current unit.
A scratchpad keeps SVs which are lexicals for the current unit and are
targets for opcodes. One can deduce that an SV lives on a scratchpad
state. With multiplicity-enabled perls, PERL_IMPLICIT_CONTEXT is also
normally defined, and enables the support for passing in a "hidden" first
argument that represents all three data structures. MULTIPLICITY makes
-mutli-threaded perls possible (with the ithreads threading model, related
+multi-threaded perls possible (with the ithreads threading model, related
to the macro USE_ITHREADS.)
Two other "encapsulation" macros are the PERL_GLOBAL_STRUCT and
Similarly, all global variables begin with C<PL_>. (By convention,
static functions start with C<S_>.)
-Inside the Perl core, you can get at the functions either with or
-without the C<Perl_> prefix, thanks to a bunch of defines that live in
-F<embed.h>. This header file is generated automatically from
+Inside the Perl core (C<PERL_CORE> defined), you can get at the functions
+either with or without the C<Perl_> prefix, thanks to a bunch of defines
+that live in F<embed.h>. Note that extension code should I<not> set
+C<PERL_CORE>; this exposes the full perl internals, and is likely to cause
+breakage of the XS in each new perl release.
+
+The file F<embed.h> is generated automatically from
F<embed.pl> and F<embed.fnc>. F<embed.pl> also creates the prototyping
header files for the internal functions, generates the documentation
and a lot of other bits and pieces. It's important that when you add
slightly differently. A flag in the SV, C<SVf_UTF8>, indicates that the
string is internally encoded as UTF-8. Without it, the byte value is the
codepoint number and vice versa (in other words, the string is encoded
-as iso-8859-1). You can check and manipulate this flag with the
+as iso-8859-1, but C<use feature 'unicode_strings'> is needed to get iso-8859-1
+semantics). You can check and manipulate this flag with the
following macros:
SvUTF8(sv)
need to enter a name and description for your op at the appropriate
place in the C<PL_custom_op_names> and C<PL_custom_op_descs> hashes.
-Forthcoming versions of C<B::Generate> (version 1.0 and above) should
-directly support the creation of custom ops by name.
+C<B::Generate> directly supports the creation of custom ops by name.
=head1 AUTHORS
=head1 SEE ALSO
-perlapi(1), perlintern(1), perlxs(1), perlembed(1)
+L<perlapi>, L<perlintern>, L<perlxs>, L<perlembed>
https://perl5.git.perl.org / perl5.git / blobdiff