[Swig-user] flite C wrapper for C#

[Mauricio H. <mhe...@te...>]

Hi:

this is my first post to the list, so first to all hi to everyone and 
let me congratulate you for such a great project it help a lot with the 
difficult and tedious task of make wrappers....

Right now I'm trying to make a simple wrapper for c# of the C API of 
flite tts engine, so I use something like this to generate the wrapper:
swig -csharp -namespace TTS -module flite flite.h

The command above generate me the correct C# files and a flite_wrap.c C 
code file, I create a shared lib from flite_wrap.c like 
linflitewrap.so.1.0.1 and I was able to call from a C# program to the 
simple flite "init"function, the declaration of that function in the 
flite.h interfaces is like: int flite_init();, the flite_wrap.c 
generated file make a definition of that function like:
SWIGEXPORT int SWIGSTDCALL CSharp_flite_init() {
...
  result = (int)flite_init();
...
And I'm able to call the function from my mono C# code like: 
TTS.flite.flite_init(); , so far all good, but currently my problem is 
with this originally function from flite.h:

float flite_text_to_speech(const char *text, cst_voice *voice, const 
char *outtype);

As you can see, I need the cst_voice type, so SWIG make this for that 
function (flite_wrap.c):

SWIGEXPORT float SWIGSTDCALL CSharp_flite_text_to_speech(char * jarg1, 
void * jarg2, char * jarg3) {
  float jresult ; char *arg1 = (char *) 0 ;  cst_voice *arg2 = 
(cst_voice *) 0 ;  char *arg3 = (char *) 0 ;  float result;
  arg1 = (char *)jarg1;  arg2 = (cst_voice *)jarg2;   arg3 = (char *)jarg3;
  result = (float)flite_text_to_speech((char const *)arg1,arg2,(char 
const *)arg3);
  jresult = result;   return jresult;}

wich seems to be ok, but in the C# code SWIG make this for the cst_voice 
type:
public class SWIGTYPE_p_cst_voice {
  private HandleRef swigCPtr;
internal SWIGTYPE_p_cst_voice(IntPtr cPtr, bool futureUse) {
    swigCPtr = new HandleRef(this, cPtr);
  }
  protected SWIGTYPE_p_cst_voice() {
    swigCPtr = new HandleRef(null, IntPtr.Zero);
  }
  internal static HandleRef getCPtr(SWIGTYPE_p_cst_voice obj) {
    return (obj == null) ? new HandleRef(null, IntPtr.Zero) : obj.swigCPtr;
  }
}
..and here begin my problems, because I can't call to any constructor of 
this type, this type is originally used in C like:
flite_init();
cst_voice *register_cmu_us_kal();
cst_voice *v;
v = register_cmu_us_kal();
flite_text_to_speech("wellcome professor", v, "play");

So I was trying to do from C# something like:
TTS.flite.flite_init(); // --> OK
TTS.SWIGTYPE_p_cst_voice v; // here I have my first problem becouse I 
don't have any public constructor..and even if I change the swig 
contructor declaration //for this type from protected to public I get a 
really ugly SIGSEGV error without any useful info.
TTS.flite.flite_text_to_speech("wellcome professor", v, "play"); //of 
course I can't call to this becouse "v" don't exist...

Here is the original declaration of cst_voice from cst_voice.h (used by 
flite.h):
struct cst_voice_struct {
    cst_features *features;
    cst_features *ffunctions;
    cst_utterance *(*utt_init)(cst_utterance *u,
                   struct cst_voice_struct *v);
};
typedef struct cst_voice_struct cst_voice;
cst_voice *new_voice();
void delete_voice(cst_voice *u);

So, basically I don't know where to start to look or check to make this 
wrapper to work, any ideas?, sugestions?

Thank you very much

Mauricio