--nextPart5717298.E47xrrF2Hp
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline

Leo Savernik wrote:
>Am Dienstag, 15. Juli 2008 schrieb Thiago Macieira:
>> Besides, my point is exactly that qt_metacall *is* the same as
>> virtual_hook. There's no need to involve signals here. Technically all
>> you needed to do was:
>>
>> void MiddleClass::publicFunction(bool b)
>> {
>> =A0 =A0 void *args[] =3D { &b };
>> =A0 =A0 int id =3D metaObject()->indexOfMethod("privateFunction(bool)");
>> =A0 =A0 qt_metacall(QMetaObject::InvokeMetaMethod, id, args);
>> }
>
>Cool, I didn't know that! It's ugly, but it should still be faster than
> a slot invocation.

The above is what the invokeMethod() call does. It hides the gory details=20
from you, but that's all.

You should use it because the above actually contains an error. It should=20
have been:

	void *args[] =3D { 0, &b };

args[0] is used to hold the return value. (Put a variable there and=20
qt_metacall will store the return value for you in it)

Note, however, that indexOfMethod takes a *normalised* name. The following=
=20
will never work (will return -1):

	indexOfMethod("privateFunction( bool )");
	indexOfMethod("privateFunction(const QString&)");
	indexOfMethod("privateFunction(char const *)");

Using invokeMethod hides the normalisation process from you and also=20
provides a modicum of type safety.

>[Declaration]
>
>> protected:
>> =A0 =A0 Q_INVOKABLE void privateFunction(bool b);
>> };
>
>Say, I don't have a Q_INVOKABLE in release x. Is then adding Q_INVOKABLE
> in release x+1 BIC?

That's a binary- and source-compatible change. Unlike the virtual table,=20
the meta object searches entries by string comparison -- the=20
indexOfMethod call above. So you can add and remove as many entries as=20
you want.

Also, note that setting the method to Q_SCRIPTABLE or making it a slot=20
makes it invokable too. (Slots can be scriptable too)

=2D-=20
=A0 Thiago Macieira =A0- =A0thiago (AT) macieira.info - thiago (AT) kde.org
=A0 =A0 PGP/GPG: 0x6EF45358; fingerprint:
=A0 =A0 E067 918B B660 DBD1 105C =A0966C 33F5 F005 6EF4 5358

--nextPart5717298.E47xrrF2Hp
Content-Type: application/pgp-signature; name=signature.asc 
Content-Description: This is a digitally signed message part.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iD8DBQBIfR3mM/XwBW70U1gRAoNEAJ9lF+AlZVl4+IN3YHu50CLeMtxOhACgwz1t
FOo8w0wnSo6oZoBLNVOjsjk=
=8dci
-----END PGP SIGNATURE-----

--nextPart5717298.E47xrrF2Hp--