Re^4: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller?

Replies are listed 'Best First'.
Re^5: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller? by salva (Canon) on Jul 08, 2014 at 11:21 UTC
Is there a Perl syntax for getting interpreter pointer? You can pass it around from XS to C using the `pTHX` and `aTHX` (and `pTHX_` and `pTHX_`) macros. Another option is to retrieve the current Perl interpreter calling `Perl_get_context()`. It is more or less explained on perlguts. Also, search CPAN for code containing `call_sv` and see how others have done it!	[reply] [d/l] [select]
Re^6: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller? by itamarat (Acolyte) on Jul 08, 2014 at 12:55 UTC
Hi, Perl_get_context() is returning NULL. That leaves me with passing Perl interpreter pointer directly from Perl to C and then use it when calling the Perl callback, right? Can you please give a hint of how should it be done? Many thanks, Itamar	[reply]
Re^7: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller? by salva (Canon) on Jul 08, 2014 at 13:17 UTC
You can find and example in the C function `custom_cmp` from the Sort::Packed module (https://metacpan.org/source/SALVA/Sort-Packed-0.08/Packed.xs). But passing the context around is done as an optimization in order to avoid calling `Perl_get_context()` repeatly. And it is not required unless the macro `PERL_NO_GET_CONTEXT` is defined. So, you are probably doing something on the wrong way. The first thing that chokes me is that if you start from the Perl side, you shouldn't be calling `perl_alloc` at all. Try remove any interpreter setup from your code, and calling some Perl function from the C side. It should just work.	[reply] [d/l] [select]
Re^8: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller? by itamarat (Acolyte) on Jul 08, 2014 at 13:52 UTC
Re^9: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller? by salva (Canon) on Jul 08, 2014 at 14:27 UTC
Some notes below your chosen depth have not been shown here
Re^5: Perl calls C calls Perl CallBack: How Perl callback use the same interpreter/context as Perl caller? by Corion (Patriarch) on Jul 08, 2014 at 11:39 UTC
I thought that `my_perl` was a variable in your C code, but I now realize that your C code gets called from Perl. I don't find a convenient way in perlguts, perlapi or perlcall, but maybe you don't even need special things like passing the Perl interpreter around as the current Perl interpreter already is a global variable.	[reply] [d/l]