Re: Q: av_push

[Reinhard Pagitsch]

Dear Nick,
Nick Ing-Simmons wrote:
Reinhard Pagitsch <[EMAIL PROTECTED]> writes:
Hi,
Muppet wrote:
On Sep 15, 2004, at 11:42 AM, Reinhard Pagitsch wrote:
If I populate an array with av_push will the SV* val a copy in the 
array or it is only a reference to it?

av_make() copies the svs you give it, but none of the other av 
functions do.  av_store() and av_push() both store in the av the 
actual pointers you give to them, which means they basically own the svs.

if in doubt, see Perl_av_store() in perl/av.c; near the end, the line 
ary[key] = val is where the pointer passed as an arg is stored in the 
internal data structure.  val's refcount is never touched.

Thank you for the information. What have I to do now? 
What ever you like ;-)
That is you can either:
 A. Leave it the way it is.
    This assumes that previous "owner" of resl SV is not 
    going to free it. As you have done a newSVxxx() in your 
    example your code is the owner and there is no problem.
   
But if "resl" had been passed to you as a parameter (owned by caller)
or found in another data structure (be that a perl AV or HV or something 
custom) then you don't own it so one of following is needed. 
 

Ok, I am the owner of "resl"  so there is no need to change my code. :-)
 B. Make a copy of each SV as you add it to the array.
      if(!check(res, res1)) {
       av_push(res,newSVsv(res1));
     }
 C. Adjust its REFCNT
      if(!check(res, res1)) {
       av_push(res,SvREFCNT_inc(res1));
     }
 

Whats about the REFCNT? Can you please explain or give me a link where I 
can read it?
The perl documentation is not very clear to me in this and many other 
cases. :-(

With av_make I 
have to know how many SV's will be stored.
But I do not know it at this time. Is the way I do it now the correct one?
Depends 

BTW is there a XS function like the strtok() in C or the split() in 
Perl? I did not find one in the Activestate documentation.
XS _is_ C code so you can use C functions.
I tryed the strtok() function but Perl crashes.
strtok() is a tricky thing - raw strtok() uses static data between calls
so it thread hostile.
I usually use split() in perl code and then pass results to the XS,
or for simple cases something like:
 

I not want to pass an arry to my XS, I want to get back an array. But I 
will keep your code in mind for further use.
Thank you.

 char *string = ...l
 char *sep;
 while ((sep = strchr(string,','))
  {
   process(string,sep-string);
   string = sep+1;
  }
 

mit freundlichen GrÃÃen,
with my best regards,
Reinhard