Trouble with using boost::bind & boost::function

Question

Following on from this question

How to pass class member functions to a method in a 3rd party library?

Quick recap is I need to pass pointers to functions to the constructor of a class called moveset in a 3rd party library with the definition of

template <class Space>
moveset<Space>::moveset(particle<Space> (*pfInit)(rng*),
          void (*pfNewMoves)(long, particle<Space> &,rng*),
          int (*pfNewMCMC)(long,particle<Space> &,rng*))

The examples provided with the library are to simply define global functions for pfInit etc, let call them f,g and h. Then call smc::moveset Moveset(f,g,h) from within a controller class;

I have attempted to implement the suggestion using boost:bind. Unfortunately, I am struggling to get this to work.

class IK_PFWrapper
{
 public:

 IK_PFWrapper(Skeleton* skeleton, PFSettings* pfSettings) ;
 smc::particle<cv_state> fInitialise(smc::rng *pRng);

... 
} ;

in a controller class

IK_PFWrapper testWrapper (skeleton_,pfSettings_);
boost::function<smc::particle<cv_state> (smc::rng *)>  f = boost::bind(&IK_PFWrapper::fInitialise, &testWrapper,_1) ; 

// the 2nd and 3rd argument will be eventually be defined in the same manner as the 1st
smc::moveset<cv_state> Moveset(f, NULL, NULL); 

The resultant compiler error is,

Algorithms\IK_PFController.cpp(88): error C2664: 'smc::moveset<Space>::moveset(smc::particle<Space> (__cdecl *)(smc::rng *),void (__cdecl *)(long,smc::particle<Space> &,smc::rng *),int (__cdecl *)(long,smc::particle<Space> &,smc::rng *))' : cannot convert parameter 1 from 'boost::function<Signature>' to 'smc::particle<Space> (__cdecl *)(smc::rng *)'
with
[
 Space=cv_state
]
and
[
 Signature=smc::particle<cv_state> (smc::rng *)
]
and
[
 Space=cv_state
]
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

Any help much appreciated

Answer 1

See demote boost::function to a plain function pointer.

boost::function (that you create with boost::bind does not automatically convert to a plain old function pointer.

I suggest creating a wrapper interface that uses boost::function, ie your example (reduced to one parameter) would look something like:

template <class Space>
moveset<Space>::moveset(boost::function<particle<Space> (rng*)> pfInit)
{
    library_namespace::moveset<Space>(
        pfInit.target<particle<Space>(rng*)>()    // parameter 1
    );
}

Creating the wrapper means you only have to deal with raw function pointers in one place. Hope that helps, and apologies for any and all errors in the code snippet!