Tom   s wrote:
> First of all, there's no references in C.
>
> While C-style casts are deprecated in C++, they may still be used.
>
> However, why was their functionality *extended* to allow casting to a
> reference?

Because references were added to the language before the new-style casts
were, and so the extension was necessary.  At that point, code was
written to use C-style casts on references, so making it illegal breaks
working code.

--
Jon Biggar
Floorboard Software
jon@floorboard.com
jon@biggar.org

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"Tom=E1s" <NULL@NULL.NULL> wrote in message=20
news:sTH8g.9041$j7.305354@news.indigo.ie...
[...]
> I propose that C-style Cast with references should be banned (i.e. they
> should not compile).
>


Treating references differently from the other types would have adverse e=
ffect=20
on templates. Since C style cast is not equivalent in general case to any=
 of c++=20
casts, it makes sense to keep it for all types instead of writing special=
ization=20
for references every time it is used. E.g.,

template<class To, class From> To c_cast(From from) { return (To)from; }

int main()
{
    int i =3D 0;
    long& l =3D c_cast<long&>(i);
}
--=20
Gene Bushuyev (www.gbresearch.com)
----------------------------------------------------------------
There is no greatness where there is no simplicity, goodness and truth. ~=
 Leo=20
Tolstoy=20

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Tom   s wrote:
>> First of all, there's no references in C.
>> While C-style casts are deprecated in C++, they may still be used.
>>
>> However, why was their functionality *extended* to allow casting to a
>> reference?
>

Jonathan Biggar wrote:
> Because references were added to the language before the new-style casts
> were, and so the extension was necessary.  At that point, code was
> written to use C-style casts on references, so making it illegal breaks
> working code.

You compiler vendor is free to issue a warning in these cases, though.


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Tom=E1s wrote:
> First of all, there's no references in C.
>=20
> While C-style casts are deprecated in C++, they may still be used.

They aren't officially called C-style casts.  They don't behave like
casts do in C really.  They aren't deprecated either.  There is even
one operating mode of the C-style cast for which there is no C++
equivelent.

>=20
> However, why was their functionality *extended* to allow casting to a=20
> reference?

Because it was needed, the other casts case later.

>=20

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First of all, there's no references in C.

While C-style casts are deprecated in C++, they may still be used.

However, why was their functionality *extended* to allow casting to a
reference?

Here's some sample code which compiles, but which I rather wish would not
compile:


void ModifyConstantObject( const int& a )
{
   ++(int&)a;

   /* This should have to be:

   ++const_cast<int&>(a);

   */
}

int main()
{
    int const a = 7;

    ModifyConstantObject(a);
}


I propose that C-style Cast with references should be banned (i.e. they
should not compile).

-Tom   s

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