Thanks for this reply - this was exactly what we needed to know.
and solved the problem we had.
Regards
Patrick McHale
"John Bandhauer" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Patrick McHale wrote:
> >
> > Thanks for all of your input - maybe I need to make things a bit
clearer.
> >
> > I wish to be able to implement:
> >
> > out string GetVersion(out string aValue);
>
> This implies that you want to return *two* strings. Is that
> really what you want?
>
> To return *one* string you do:
>
> // idl
> string getVersion();
> // or better...
> readonly attribute string version;
>
> You call from JS:
>
> var foo = bar.getVersion();
> // or better...
> var foo = bar.version;
>
> Implementation in C++ (same for either method or attribute decl)
>
> NS_IMETHODIMP X::GetVersion(char **_retval) {
> static const char version[] = "X 1.1";
> *_retval = reinterpret_cast<char*>(
> nsMemory::Clone(version, strlen(version)+1));
> return (*_retval) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
> }
>
> To return *two* strings you do:
>
> string getVersion(out string aSecondOutString);
>
> You call from JS:
>
> // this is why multiple out params are to be avoided!
> var secondObj = {};
> var foo = bar.getVersion(secondObj);
> var secondString = secondObj.value;
>
> John.
>
> >
> > so that I can obtain a string returned from the C++ code via javascript
in
> > this fashion. Is this possible?.
> >
> > All I have been able to use so far is:
> >
> > void GetVersion(out string aValue)
> >
> > This returns nothing but a void as a return value. In order to minimize
the
> > changes necessary to our present
> > Javascript code I need to be able to return a string as a function
return -
> > and not from a function parameter
> > return value.
> >
> > Thanks
> >
> > Patrick McHale
> > Powerlan USA.
> >
> > "Rick Parrish" <[EMAIL PROTECTED]> wrote in message
> > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > > Patrick McHale wrote:
> > >
> > > > In our IDL file we have tried using
> > > >
> > > > string GetVersion();
> > > >
> > > > The idl file generates:
> > > >
> > > > NS_METHOD GetVersion(char * _retval)
> > > >
> > >
> > >
> > > The C++ class interface stub should be producing something like
> > >
> > > NS_METHOD GetVersion([out, retval] char ** _retval);
> > >
> > > You could also experiment with making the function a readonly
> > > attribute from IDL as in ...
> > >
> > > attribute readonly string GetVersion;
> > >
> > > From JavaScript you would call the method using syntax similar
> > > to the IDL description. From C++ you would use the latter syntax.
> > >
> > > // JS
> > > var x = component.GetVersion();
> > >
> > > // C++
> > > char *pStr = NULL;
> > > nsResult ret = pObj->GetVersion(*pStr);
> > > // do something with pStr and then ...
> > > nsMemory::Free(pStr);
> > > // its caller's job to release the returned string's memory.
> > >
> > >
> > > > My question is - can we still use this method and how is
> > > > this implemented. At the present time is to write Java Glue to
achieve
> > > > this - but this is not seamless and will require a large amount of
glue
> > to
> > > > be implemented. We want to avoid having thousands of tech support
calls
> > and
> > > > wish to be able to continue using original HTML code with minimal
> > changes
> > > > necessary to implement XPCOM.
> > >
> > >
> > > I assume you meant JavaScript and not Java. Using XPCOM you can access
> > > just about any property or method on an XPCOM component.
> > >
> > >
> > > > Above is an example using the method GetVersion which produces a
return
> > > > string. In actuality we have at least 30 other routines that need to
be
> > > > setup.
> > >
> > >
> > > It isn't clear to me whether you are needing to implement your own
> > > XPCOM components. If that is the case, you can write them in C++ or
> > > JavaScript and then manipulate them from your XUL or HTML embedded
> > > JavaScript.
> > >
> > > Post here or email me directly if you need help on this.
> > >
> > >
> > > > With Thanks
> > > >
> > > > Patrick McHale
> > > > Software Engineer
> > > >
> > > > Paul Baxter
> > > > Principal Software Engineer
> > > >
> > > > Powerlan U.S.A.
> > >
> > >
> > > Regards,
> > > Rick
> > >
