XS: SvOK ? SvPV_nolen : NULL

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

I've C library with function expecting char* param which must be NULL in some cases. I wish to use it from perl this way:

c_func(undef); # NULL param
c_func('');    # empty string param
c_func(123);   # string '123' param
c_func('qwe'); # string 'qwe' param
[download]

Current XS realization:

void
c_func(param)
    char *    param = SvOK(ST(0)) ? SvPV_nolen(ST(0)) : NULL;
[download]

This task sounds like standard opration, so is there exists simpler way, without ugly "SvOK ? SvPV_nolen : NULL" chain?

Comment on XS: SvOK ? SvPV_nolen : NULL Select or Download Code

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Re: XS: SvOK ? SvPV_nolen : NULL by creamygoodness (Curate) on Jun 08, 2006 at 15:12 UTC
Provided that you don't want to be warned when the argument is undef, your code is correct. -- Marvin Humphrey Rectangular Research ― http://www.rectangular.com	[reply]
Re: XS: SvOK ? SvPV_nolen : NULL by wazzuteke (Hermit) on Jun 08, 2006 at 19:38 UTC
If you are trying to ditch the `SvOK(SV)` ternary, you could add extra validation on the Perl side before calling `c_func` For example: `# Assuming this is within the .pm package, and you are # only allowing a single parameter # as (what looks to be) defined in your XS c_func( ( ( defined( $_[0] ) ) ? $_[0] : '' ) );` [download] Where you can implicitly force the `SvOK` check in Perl-land. Though, this would simply move the ternary into Perl rather than in the XS; maybe what you are looking for. Hope that helps! `print map{chr}(45,45,104,97,124,124,116,97,45,45);` ... and I probably posted this while I was at work => whitepages.com \| inc.	[reply] [d/l] [select]