Re: cni converting String args[]

[Andi Vajda <andi at osafoundation dot org>]

I don't see in your code where you allocate the memory for the strings to be 
contained in char *arguments[argc] and where you add the terminating '\0' to 
these buffers. JvGetStringURFRegion expects a pre-allocated buffer to receive 
the characters from the java string. Also, the length of that pre-allocated 
buffer should be computed with JvGetStringUTFLength() + 1 as the number of 
unicode chars in your java string, as returned by the length() method, is not 
usually the number of utf-8 bytes needed to represent it (unless you stick to 
strict ascii).

Andi..

On Fri, 10 Dec 2004, Little-John wrote:

> * littlejohn@paranoici.org (littlejohn@paranoici.org) ha scritto:
> > * Andrew Haley (aph@redhat.com) ha scritto:
> > > >       arguments[i] = (char *) elements(argsElements[i]->getBytes());
> > >
> > > If you want chars, you'll need an encoding -- elements returns a
> > > jchar*.  Try JvGetStringUTFRegion.
> >
> >  ok, I'll let you know
>
> jint A::init(JArray< ::java::lang::String *> *args) {
>
>  int argc = 0;
>  char* arguments[argc];
>
>  if (args != NULL) // It's a very bad day otherwise
>  {
>    argc = args->length;
>    arguments[argc];
>
>    /*
>    * convert the JArray<String*>*  in char**
>    * so in a way suitable for VLC_Init
>    */
>    ::java::lang::String** argsElements = elements(args);
>
>    for (int i = 0; i < argc; i++) {
>      ::java::lang::System::out->println(argsElements[i]->length());
>      JvGetStringUTFRegion(argsElements[i], 0,
>      argsElements[i]->length(), arguments[i]);
>      printf("library: %s\n", arguments[i]);
>    }
>  }
>  return 0;
> }
>
> does not work. If i issue the command:
>
> % A --help --helpp
>
> i get
> 6 (the length of --help)
> library: --help (the printf)
> 7 (the length of --helpp)
> Exception in thread "main" java.lang.NullPointerException
>
> debugging with gdb, I see a strange thing. Maybe related to the
> gc. On the second iteration, just after the JvGetStringUTFRegion the
> arguments array is:
>
> (gdb) print arguments
> $1 = {0x0, 0x0}
>
> I can understand why.
>
> lj