in reply to Re^3: How do I test the validity of a CODE reference?
in thread How do I test the validity of a CODE reference?

Looks like they both operate on the same thing (the CV*) to me. (If not, please explain, since I'm not very familiar with this stuff.) So the question is why does Perl and your function use different tests to determine the same thing? 
#define CvROOT(sv)      ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_root
#define CvXSUB(sv)      ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_xsub
 
#define CvOUTSIDE(sv)   ((XPVCV*)SvANY(sv))->xcv_outside

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Re^5: How do I test the validity of a CODE reference?
by syphilis (Archbishop) on Aug 08, 2008 at 08:33 UTC
    Looks like they both operate on the same thing (the CV*) to me

    Yes - when you descend to that level they become very similar, indeed :-)

    So the question is why does Perl and your function use different tests to determine the same thing?

    Good question. My approach won't work on perl-5.6.2, so perhaps history and portability might be part of the explanation. But there could, of course, be other reasons. (I couldn't even get correct results on perl-5.6.2 with CvROOT and CvXSUB.)

    Cheers,
    Rob
[reply]

      Yes - when you descend to that level they become very similar, indeed :-)

      At a high level:
      validate $xdefined &$xref $x && defined &$x
      code refreturns resultreturns resultreturns result
      sub namediesreturns resultreturns false
      other refsdiesdiesdies
      undefined?stringifiedreturns false

      I couldn't even get correct results on perl-5.6.2 with CvROOT and CvXSUB

      That's odd, because defined and sub calls use CvROOT(cv) || CvXSUB(cv) in 5.6.2 as well.

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