Question

I’m starting to write a library and considering its interface. Previous libraries I’ve written all use raw pointers (both internally and in its interface), and now I want to try the smart pointer library that comes with VS2010.

1. Should the interface use smart pointers? (Possibly forcing the library users to use smart pointers too?)
2. Would it be messy if the interface uses raw pointers but the library uses smart pointers internally? (Is it even possible? shared_ptr doesn’t have a release() method…)
3. Can two c++0x compliant smart pointer libraries (say boost and VS2010) be used interchangeably? (say I use VS2010 to write my library and the users use boost)

Please help 🙂

Answer 1

It is imposable to answer those question without understanding a lot more about your design principles and how you expect the library to be used.

So I can only answer based on my experience and how I like my libraries to be used.

1. Yes.
2. Yes. Don’t do it.
3. Its probably not a good idea to mix them (though I have never tried).
   But you can compensate for this:
   As most open source is distributed as source you can build your source so that it can be configured for use in many environments.

For Example:

#if   defined(MY_PROJ_SHARED_PTR_FROM_BOOST)

#include <boost/shared_ptr.hpp>
#define MY_PROJ_SHARED_PTR_NAMESPACE    boost

#elif defined(MY_PROJ_SHARED_PTR_FROM_STD)

#include <memory>
#define MY_PROJ_SHARED_PTR_NAMESPACE    std

#elif defined(MY_PROJ_SHARED_PTR_FROM_TR1)

#include <tr1/memory>
#define MY_PROJ_SHARED_PTR_NAMESPACE    std::tr1

#else
#error "MY_PROJ_SHARED_PTR_FROM_<XXX> not defined correctly"
#endif


namespace X
{
    using ::MY_PROJ_SHARED_PTR_NAMESPACE::shared_ptr;
}


int main()
{
    X::shared_ptr<int>  data;
}

I am sure there are other ways to do this.
But it is late.