Ambiguous template function, best way to solve it...

  • Thread starter Thread starter Mark
  • Start date Start date
M

Mark

Hi,
I've got a template function

move_by( rect<T>&, T x, T y) being called as

rect<float> r;
move_by( r, 3.0, 4.0 );

However, i'm getting stupid ambiguities when I use
floating point numbers.

event_handler.cpp(43) : error C2782: 'void ' : template parameter 'T' is
ambiguous
could be 'double'
or 'float'

This message is referring to the x,y arguments.

Do I really have to specialise for these types? It
seems rediculous and defeats the purpose of having templates
to begin with.

Any ideas?

Thanks,
Mark.
 
Hi,
I've got a template function

move_by( rect<T>&, T x, T y) being called as

rect<float> r;
move_by( r, 3.0, 4.0 );

However, i'm getting stupid ambiguities when I use
floating point numbers.

event_handler.cpp(43) : error C2782: 'void ' : template parameter 'T' is
ambiguous
could be 'double'
or 'float'

This message is referring to the x,y arguments.

Do I really have to specialise for these types? It
seems rediculous and defeats the purpose of having templates
to begin with.

Any ideas?
Click to expand...

Your template says that it takes a rect<T> and T's. You are passing it
a rect<float> and two doubles, so unsurprisingly it doesn't know which
one you want. You could do:

//all floats
rect<float> r;
move_by( r, 3.0f, 4.0f);

or
//all doubles
rect<double> r
move_by( r, 3.0, 4.0);

//allow mix of float and double.
or change move_by to
template <class T, class U>
void move_by(rect<T>&, U x, U y);

Tom
 
Hi Tom
I had forgotten that the f suffix existed :)
Works now! Still considering if I need the
dual type version...

Thanks very much,
Mark.
 
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