Calling perl builtins from C

Cine has asked for the wisdom of the Perl Monks concerning the following question:

How do I make a call to a builtin function from XS?
This doesnt work:

use Inline C => q{
void c_time() {
  SV* val = get_cv("localtime", FALSE);
  if (!val) croak("Name does not exists!");
  call_sv(val,GIMME_V);
}
};
print scalar c_time();
[download]

This does

sub helper {
  localtime();
}
use Inline C => q{
void c_time() {
  SV* val = get_cv("helper", FALSE);
  if (!val) croak("Name does not exists!");
  call_sv(val,GIMME_V);
}
};
print scalar c_time();
[download]

T I M T O W T D I

Comment on Calling perl builtins from C Select or Download Code

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Re: Calling perl builtins from C by chromatic (Archbishop) on Aug 04, 2003 at 20:30 UTC
`localtime` isn't implemented in Perl as a function. It's actually a pp code. As of Perl 5.8.0, see `pp_sys.c`. That actually won't help you, either, because it takes and returns internal Perl data structures. All of this is mostly academic, though, because there's already a C `localtime` call, if you really need it. I'm not good at XS, but I'd break my code into smaller chunks and do as little in C as possible; if you find yourself needing to call internal Perl pp codes, you could probably refactor your code down more sooner than you could figure out how to fake up what the pp code actually needs. (See again my disclaimer about not being good at XS, though.)	[reply] [d/l] [select]
Re: Calling perl builtins from C by revdiablo (Prior) on Aug 04, 2003 at 20:14 UTC
You might be interested in Calling builtin functions from Inline::C from earlier today. It seems to be pretty much identical.	[reply]
Re: Re: Calling perl builtins from C by Cine (Friar) on Aug 04, 2003 at 20:16 UTC
Yes, just noticed it. Two of the same of this kind of questions on one day? T I M T O W T D I	[reply] [d/l]