Example header for a shared library loader that loads plugin objects from the pluginAPI.h header.

sharedLibrary.h

#ifndef __SHARED_LIB_H__
#define __SHARED_LIB_H__

#include <string>

#include "pluginAPI.h"

//-----------------------------------------------------------------------------
//  Shared Library loading object (Used for RAII purposes).
//-----------------------------------------------------------------------------
class sharedLibrary {
    private:
        pluginFactory_t pFactory    = nullptr;
        pluginDeleter_t pDeleter    = nullptr;
        plugin*         pPlugin     = nullptr;
        void*           pHandle     = nullptr;
        
        bool loadFactoryMethod();
        bool loadDeleterMethod();
    
    public:
        /**
         * Destructor to unload the shared libray when *this goes out of scope.
         * It is the same thing as calling the "unload()" method.
         */
        ~sharedLibrary();
        
        /**
         * Default Constructor.
         */
        sharedLibrary() = default;
        
        /**
         * The Copy constructor has been removed in order to avoid having two
         * classes delete the same handles to a loaded library
         */
        sharedLibrary(const sharedLibrary&) = delete;
        
        /**
         * Move constructor may be used to transfer ownership of *this object's
         * resources to something such as an STL container.
         */
        sharedLibrary(sharedLibrary&&);
        
        /**
         * The Copy operator has also been removed in order to avoid having two
         * classes delete the same handles to a loaded library
         */
        sharedLibrary& operator=(const sharedLibrary&) = delete;
        
        /**
         * Move operator may also be used to transfer ownership of *this
         * object's resources.
         */
        sharedLibrary& operator=(sharedLibrary&&);
        
        /**
         * Load a shared library from a file.
         */
        bool load(const std::string& filename);
        
        /**
         * Unload all resources and file handles used by *this.
         */
        void unload();
        
        /**
         * Get a pointer to the plugin object that was loaded from a file by
         * *this. Returns NULL if nothing exists.
         */
        const plugin* getPlugin() const;
        
        /**
         * Helper method that will be used to determine if a referenced filen
         * name is a shared library that can be loaded into *this.
         */
        static bool isSharedLib(const std::string& filename);
};

#endif /* __SHARED_LIB_H__ */