Thread: creating a new instance of a function?

Originally posted by DeepBlackMagic
its required for an index.

Try using functors (function objects) instead. STL has great support for them, and you could use unique addresses from instances as your index. Additionally, you could make indices like this:

Code:

#include <functional>

struct my_func : public std::binary_function<std::string, int, void>
{
  void operator()(std::string str, int x)
  {
    // ...
  }
};

void foo()
{
  std::unary_function<std::string, void> func1 = std::bind2nd(my_func(), 1);
  std::unary_function<std::string, void> func2 = std::bind2nd(my_func(), 2);
}

Originally posted by Bubba
True, but in this case that is not needed. My advice is to try and use the language the way it was designed to be used. Any questions - check my sig.

This is one way it was designed to be used. They actually simplify things. Since you can have multiple instances, creating a unique index for each one is nice and simple.

Here is perhaps a simpler example:

Code:

struct func
{
  func(int x) : _index(x) {}
  void operator( ) (std::string str)
  {
  // ....
  }
private:
  int _index;
};