Re: Calling PERL from C code - How to "build" a hash on the PERL stack before calling the function?

In perlguts,Working With HVs, the code to create a new HV ("Hash Variable"?) is:

HV* my_hash;
my_hash= newHV();
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Then, you use hv_store() and hv_fetch to read/write the keys and values of the hash.

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Re^2: Calling PERL from C code - How to "build" a hash on the PERL stack before calling the function? by itamarat (Acolyte) on Jul 07, 2014 at 09:12 UTC
Hi, You have helped a lot! Thank you! How do I push the HV to the PERL stack? Currently I use: XPUSHs(sv_2mortal(newSViv((unsigned int)cbCtx))); To push integer to the stack. I've searched for 'newSVhv' and it is not present. How should it be done? Thanks again! Itamar	[reply]
Re^3: Calling PERL from C code - How to "build" a hash on the PERL stack before calling the function? by Corion (Patriarch) on Jul 07, 2014 at 09:16 UTC
perlcall has a section on Returning a List of Values. If you don't want to flatten the hash into a list of values, consider returning a reference to the hash, by returning `newSVrv(HV)` (or whatever the magic C incantation would be, according to perlguts.	[reply] [d/l]
Re^3: Calling PERL from C code - How to "build" a hash on the PERL stack before calling the function? by tobyink (Canon) on Jul 07, 2014 at 13:53 UTC
You can't push an HV onto the stack. Perl functions are only ever passed a list of scalars! You can however pass a reference to a hash, which the Perl function can dereference to access the original hash. Or you can pass alternating pairs of keys and values onto the stack. In which case, the Perl function can assign `@_` to a lexical hash (`my %args = @_`). toby döt ink	[reply] [d/l] [select]