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Dennis Jones
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 Posted: Wed Jun 08, 2005 4:23 am Post subject: incorrect overloaded function called? |
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Hi,
I am seeing some strange behavior in an overloaded function call. I have
something like this:
void func( TDateTime t )
{
}
void func( int i )
{
}
Now, suppose I call func() like this:
func( TDateTime( 0, 0, 0, 0 ) );
But when I do this, "func( int )" gets invoked!!
But if I do this instead:
TDateTime t( 0, 0, 0, 0 );
func( t );
....then "func( TDateTime )" gets invoked as expected. Now, I know TDateTime
has an int() operator, but shouldn't the type system see that func(
TDateTime ) is a better match than func( int ) for the first case?
- Dennis
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Remy Lebeau (TeamB)
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| Posted: Wed Jun 08, 2005 5:46 am Post subject: Re: incorrect overloaded function called? |
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"Dennis Jones" <nospam (AT) nospam (DOT) com> wrote
| Quote: | void func( TDateTime t )
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You should pass your object by reference:
void func(const TDateTime &t)
Gambit
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Dennis Jones
Guest
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| Posted: Wed Jun 08, 2005 6:22 am Post subject: Re: incorrect overloaded function called? |
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"Remy Lebeau (TeamB)" <no.spam (AT) no (DOT) spam.com> wrote
| Quote: |
"Dennis Jones" <nospam (AT) nospam (DOT) com> wrote in message
news:42a672c5$1 (AT) newsgroups (DOT) borland.com...
void func( TDateTime t )
You should pass your object by reference:
void func(const TDateTime &t)
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Actually, I do, and that is the problem. However, I don't have a 'const'
modifier on it, and that also appears to be a key element in the problem.
For instance, the following prototype does not match (which is what I had):
void func( TDateTime &t )
....while both of these do:
void func( TDateTime t )
void func( const TDateTime &t )
And now that I think about it, I have a vague understanding of why this is:
the object being passed is a temporary, so it can only be matched by a const
reference or a non-reference (because temporaries cannot be changed).
Otherwise the other function (with an int argument), although it requires an
implicit type conversion, is a better match because it is not a reference.
Thanks for the bump in the right direction.
- Dennis
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Alan Bellingham
Guest
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| Posted: Wed Jun 08, 2005 8:15 am Post subject: Re: incorrect overloaded function called? |
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"Dennis Jones" <nospam (AT) nospam (DOT) com> wrote:
| Quote: | the object being passed is a temporary, so it can only be matched by a const
reference or a non-reference (because temporaries cannot be changed).
Otherwise the other function (with an int argument), although it requires an
implicit type conversion, is a better match because it is not a reference.
|
Absolutely correct.
Alan Bellingham
--
Me <url:mailto:alanb (AT) episys (DOT) com> <url:http://www.doughnut.demon.co.uk/>
ACCU - C, C++ and Java programming <url:http://accu.org/>
The 2004 Discworld Convention <url:http://dwcon.org/>
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Dennis Jones
Guest
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| Posted: Wed Jun 08, 2005 3:59 pm Post subject: Re: incorrect overloaded function called? |
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"Alan Bellingham" <alanb (AT) episys (DOT) com> wrote
| Quote: | "Dennis Jones" <nospam (AT) nospam (DOT) com> wrote:
the object being passed is a temporary, so it can only be matched by a
const
reference or a non-reference (because temporaries cannot be changed).
Otherwise the other function (with an int argument), although it requires
an
implicit type conversion, is a better match because it is not a
reference.
Absolutely correct.
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Thanks for the confirmation, Alan!
- Dennis
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