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boost::bind on overloaded methods

Started by wild_pointer Jan 22, 2006 at 5:44 PM 5 replies 12.7k views

Original Post

Jan 22, 2006 at 5:44 PM

Is there a way to let bind know which version of an overloaded method I'd like to use?


struct Foo {
  void Bar(int x);
  void Bar(float x);
};

// --

Foo* foo = new Foo();
boost::bind(&Foo::Bar, foo, _1); // 100+ errors!

cypherx

Jan 22, 2006 at 5:51 PM

I haven't used Boost bind, but have you tried specifying the function signature?

Would boost::bind(&Foo::Bar(int), foo, _1); work?

Also, what is "new Foo();"? Is that the same as "new Foo;"?

-Alex

dave_

Jan 22, 2006 at 5:51 PM

The compiler cant tell which one you want to use, you have to specify the template parameters. HAve a look at the documentation for examples of how to do this. Theres an example in the section titled Using bind with function objects

Dorvo

Jan 22, 2006 at 5:55 PM

Here's the direct link that dave_ was referring to.

Fruny

Jan 22, 2006 at 5:58 PM

When taking the address of an overloaded function, you specify which overload you are referring to by casting the pointer to the appropriate type:

boost::bind( static_cast<void (Foo::*)( int )>(&Foo::Bar) , foo, _1);boost::bind( static_cast<void (Foo::*)(float)>(&Foo::Bar) , foo, _1);

Breaking the process into two steps (take the pointer, pass it to bind) may make things clearer.

wild_pointer

Jan 22, 2006 at 6:01 PM

Quote:
Original post by dave_
The compiler cant tell which one you want to use, you have to specify the template parameters. HAve a look at the documentation for examples of how to do this. Theres an example in the section titled Using bind with function objects

I believe the template argument is only for specifying return type? Perhaps I've misunderstood.

wild_pointer

Jan 22, 2006 at 6:06 PM

Quote:
Original post by Fruny
When taking the address of an overloaded function, you specify which overload you are referring to by casting the pointer to the appropriate type:
boost::bind( static_cast<void (Foo::*)( int )>(&Foo::Bar) , foo, _1);boost::bind( static_cast<void (Foo::*)(float)>(&Foo::Bar) , foo, _1);
Breaking the process into two steps (take the pointer, pass it to bind) may make things clearer.

Thank you!

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