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in reply to Re: Passing a very large string by reference to a c library
in thread Passing a very large string by reference to a c library

Thks,

This is what I've been looking at. The example doesn't use references, though example 6 does. I can try to meld both together so that I can call:

find_index($key, \$data);

I guess a lot depends on how SvPV works. If it copies the data then I need another method.

dino

  • Comment on Re: Re: Passing a very large string by reference to a c library

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Re: Re: Re: Passing a very large string by reference to a c library
by dino (Sexton) on Jul 12, 2001 at 18:37 UTC
    I've got it to work with:

    unsigned long
find_index (key, data)
        unsigned long         key
        SV    *               data
    INIT:
       STRLEN          datalen;
       char * s;
       if ((!SvROK(data))
          || (SvTYPE(SvRV(data)) != SVt_PV))
       {
          XSRETURN_UNDEF;
       }
       s = SvPV(SvRV(data), datalen);
    CODE:
      RETVAL = find_index (key, s, datalen);
    OUTPUT:
      RETVAL

    I'm still not sure if SvPV copies its internal data somewhere or just returns a pointer to it.

    Comments please

    dino

[reply]
      And finally,

      from the perlapi manpage:

       SvPV    Returns a pointer to the string in the SV, or a
         stringified form of the SV if the SV does not con-
         tain a string.  Handles 'get' magic.
 
         char*   SvPV(SV* sv, STRLEN len)

      so that should do it

      dino

[reply]

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