Re: vector of generic function pointers

From:
inquisitive <khattri.vaibhav@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 27 Feb 2008 02:14:03 -0800 (PST)
Message-ID:
<c3544877-18c2-4df4-97f1-39c322891cfe@c33g2000hsd.googlegroups.com>
On Feb 27, 2:07 pm, Triple-DES <DenPlettf...@gmail.com> wrote:

On 27 Feb, 08:04, inquisitive <khattri.vaib...@gmail.com> wrote:

Is it possible to have a vector of generic function pointers?

I am able to devise a generic function pointer, this way:

template <typename elemType, elemType (*function)(std::string&)>
struct Method
{
    inline elemType operator()(std::string & property)
    {
        return function(property);
    }

};

It is instantiated as:
 Method <int, methodOne> numberMethod;

Now I want to create a vector of these generic function pointers, how
do I declare such a vector and how do I initialize its elements:


You could make a common base class:

template<typename E>
struct MethodBase
{
  virtual E operator()(const std::string&) const = 0;};

template<typename E, E(*f)(const std::string&)>
struct Method : public MethodBase<E>
{
  // ...

};

int main()
{
  std::vector<MethodBase<int> *> v;
  v.push_back( new M<int, someFunction>);
  v.push_back( new M<int, someFunction2>);
  // cleanup

}


Thank you, but I want the independence to have different return-types
for my functions.

The problem that I was facing is to as to how could I templatize the
parameter passed on to the vector at its declaration.
My core issue is to create a generic function pointers with the
signature known in advance but not the actual type of the parameter
and return value. And then how do I build a collection of such generic
function pointers.

A second question is, if the vector and the functions are part of a
class, how would the declaration look like.

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