Hi,

I'm working with a C library that returns an array of strings. So that is type PPChar. I C library does the array allocation, but doesn't do the freeing of the array.

How am I supposed to free an array of PChar strings? I think I need to improve my iteration too, because I'm moving the pointer of wlst, so I probably need to make a backup of the original pointer before the iteration.

My code looks as follows:

---------------------------------
 var
    s: PChar;
    wlst: PPChar;
    i: integer;
    n: integer;
  begin
      // Returns an array of PChar strings. i = number of elements in array
      i := Hunspell_suggest(SpellPtr, wlst, s);
      if i > 0 then
        writeln(Format('  %d suggestions:', [i]));
      for n := 1 to i do
      begin
        writeln('     ', UTF8Decode(wlst^));
        Inc(wlst, SizeOf(Pointer));
      end;
    end;
---------------------------------

Regards,
- Graeme -

In our previous episode, Graeme Geldenhuys said:

The array is 0 terminated, iow the last array of pchar is nil.

var p2 : ppchar;
If assigned(p) then
  begin
    p2:=p;
    while assigned(p2) do
      begin
        cfree(p2);
        inc(p2);
      end;
    cfree(p);
  end;

where cfree is the free() corresponding to the malloc with which it was allocated in the lib. (usually libc's)

2010/1/19 Marco van de Voort :

where cfree is the free() corresponding to the malloc with which it was allocated in the lib. (usually libc's)

Thanks for the repy. In the end I found the library I was using was old. The newer library has a function that does the free'ing of that list for me.