Perl XS and null argument values

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February 5th, 2013, 04:24 AM

zby

Contributing User

Join Date: Jul 2003

Location: Prague, Czech Republic

Posts: 867

Time spent in forums: 6 Days 23 h 41 m 23 sec
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Perl XS and null argument values

I need to write an interface to a tiny C library provided a collegue of mine.
I began to write the code like this:

Code:

int
verify(char *datafile,char *signfile,char *cacert);
    CODE:
          RETVAL=CLIB_verify(datafile,signfile,cacert);
    RETURN:
          RETVAL;

The trouble is with the NULL argument values which are not passed as NULL, but rather as empty (zero length).

1. How can I pass NULL argument values to the C function of CLIB_verify?
2. Is there a way to convert such zero length values to NULL centrally. Eg. in a typemap or do I have to declare/convert in every function where required?

Thank you.

February 5th, 2013, 06:45 AM

zby

Contributing User

Join Date: Jul 2003

Location: Prague, Czech Republic

Posts: 867

Time spent in forums: 6 Days 23 h 41 m 23 sec
Reputation Power: 69

I have found a (so far) working solution like this:

Code:

int
verify(datafile,signfile,cacert);
    char * datafile = SvOK(ST(0)) ? SvPV_nolen(ST(0)) : NULL;
    char * signfile = SvOK(ST(1)) ? SvPV_nolen(ST(1)) : NULL;
    char * cacert = SvOK(ST(2)) ? SvPV_nolen(ST(2)) : NULL;
    CODE:
          RETVAL=CLIB_verify(datafile,signfile,cacert);
    RETURN:
          RETVAL;

Someone having another and better solution, please reply to this. I'll glad.
Thank you.

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