RE: Return Value : Constants

[Soumen Das]

Sorry it says, typemap not defined. Could the typemap be the same as
wchar_t* ?

-----Original Message-----
From: Soumen Das [mailto:[EMAIL PROTECTED]]
Sent: Thursday, December 14, 2000 4:06 PM
To: Nick Ing-Simmons
Cc: [EMAIL PROTECTED]
Subject: RE: Return Value : Constants


wchar_t **
===========
One of the C++ API has it's prototype as..
long ConfirmAdd(void * pvChild, wchar_t* *psError=NULL);

I tried to follow your suggestion but it says wchar_t** prototype not
defined. Do I have to define a prototype for the same ?

-----Original Message-----
From: Nick Ing-Simmons [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, December 12, 2000 3:28 PM
To: [EMAIL PROTECTED]
Cc: Nick Ing-Simmons; [EMAIL PROTECTED]
Subject: RE: Return Value : Constants


Soumen Das <[EMAIL PROTECTED]> writes:
>Thanks. I have perl 5.6 installed. I looked at the typemap and i find both
>mapped as follows..
>char *         T_PV
>wchar_t *      T_PV
>Is there something wrong here ?

That is ok as an INPUT ( perl -> lib ) typemap but no good
for the other direction.

>
>The other thing if I had to map const wchar_t**, how would I do it ? I also
>have API's with such return types.

Generally speaking SomeType **  is normally passing/returning a list.
IMHO it is better to do such things long-hand in the CODE/PPCODE
section so that you can use perl list idiom.

e.g. (very skeletal!)

YourFunction(...,@list);

becomes something like:

YourFunction(...,@list)
CODE:
 {
  wchar_t **list;
  Newz('X',list,items-start,wchar_t *);
  for (i=start; i < items; i++)
   list[i] = sv_to_wchar_converter_you_devise(ST(i));
  YourFuntion(...,list,...);
  Safefree(list);
 }

and

@list = YourFunction();

becomes

void
PPCODE:
 {
  wchar_t *list[SIZE];
  int n = 0;
  YourFunction(...,list,...);
  while (*list) /* or whatever indicates number */
   {
    XPUSHs(sv_2mortal(your_wchar_to_sv_converter(list[n++]));
   }
  XSRETURN(n);
 }


But you are still going to have to UTF-8 map the wide chars somehow.
And no perl has that yet. In development track there are parts
of it _if_ you know wchar_t is holding Unicode then
you could do use uv_to_utf8() char at a time.
If wchar_t is in some other encoding then Encode.pm may help.


>But if you want perl to see a sane string you need
>  (a) perl5.6.0 or later
>  (b) something to translate wchar_t * into UTF-8 encoded Unicode.
>      This is still work-in-progress
--
Nick Ing-Simmons