On 28/01/03 22:28 +0000, Miah Gregory wrote:
> [subscribed to list]
>
> Hi all,
>
> Firstly, my apologies if this has been covered before, I've had a look
> through the archive, but I couldn't find anything relevant.
>
> I'm trying to re-implement a fairly simple perl subroutine in C, and
> inline it. Problem is, though, it takes as an argument, a 'string' of
> data, and that data may contain NUL's. This means I can't simply use a
> char * as the type.
>
> Another problem is how I should return the two results. It would be nice
> if I could return them in the same way as the perl subroutine. Looks as if
> I need to set the return type as 'void', and use Inline_Stack_*, but
> again, how do I pass back a 'string' that contains NUL's. I'm also not
> sure about how to allocate the memory for these. I saw newSVpvf mentioned
> on the mailing list, but it doesn't appear to take a length.
>
> Where can I find out more about things like newSVpvf and the rest of these
> macros/functions?
>
> I'll paste the perl code here, just for reference, so the above might seem
> clearer.
>
> sub splitatoffset
> {
> my ($data, $length) = @_;
> my ($a, $b);
>
> return ($data, "") if ($length > length($data));
> $a = substr($data, 0, $length);
> $b = substr($data, $length);
>
> return ($a, $b);
> }
Perl SV-s contain a string pointer and a length. So I would use a SV*
for input and output, and use the 'SvPV' macro to get the pointer and
length.
SV* splitatoffset(SV* string) {
char* str_ptr;
STRLEN str_len;
str_ptr = SvPV(string, str_len);
printf("The length of '%s' is %d\n", str_ptr, str_len);
}
I'll let you take it from there.
Cheers, Brian
> Before I get flamed, I'm not looking for a complete solution (although if
> someone does that, I'll be the last to complain), but just enough to get
> the perl glue in place and working. The C itself should be simple enough.
BTW, we keep the burner pretty low around here :)
