Defined in <plugin/PluginRegister.hh>.

#define REGISTER_WITH_CONFIG( CLASS, BASE, CONFIG )
#define REGISTERBYNAME_WITH_CONFIG( NAME, CLASS, BASE, CONFIG )

Register CLASS with both a default factory and a config factory, so both create overloads work:

BASE::create( key )          // -> new CLASS()
BASE::create( key, cfg )     // -> new CLASS( std::any_cast<CONFIG const&>( any(cfg) ) )

REGISTER_WITH_CONFIG(C, B, Cfg) uses key "C"; REGISTERBYNAME_WITH_CONFIG("n", C, B, Cfg) uses key "n".

Requirements

• CLASS derives from BASE.
• CLASS has an accessible CLASS() and CLASS( CONFIG const& ).
• CONFIG is copyable (it is stored in std::any).

The type check

The config factory is:

static Base* CreateFromConfig( std::any const& cfg )
{
    return new T( std::any_cast< Config const& >( cfg ) );
}

The host's create(key, x) builds std::any( x ) from x's concrete type. std::any_cast<Config const&> succeeds only if that concrete type is exactly Config — otherwise std::bad_any_cast. There is no conversion, inheritance slicing, or narrowing: create("Circle", 42) (an int) does not match Circle::Config.

Example

// Circle.cpp  → libCircle.so
class Circle : public Shape
{
public:
    struct Config { unsigned int r = 0; };

    Circle()                       : radius( 0 )      {}
    explicit Circle( Config const& c ) : radius( c.r ) {}
    // ... overrides ...
private:
    unsigned int radius;
};

REGISTER_WITH_CONFIG( Circle, Shape, Circle::Config );

Host:

auto a = Shape::create( "Circle" );                       // radius 0
auto b = Shape::create( "Circle", Circle::Config{ 42 } ); // radius 42
auto c = Shape::create( "Circle", 42 );                   // throws std::bad_any_cast

Notes

• Convention in the shipped example: the Config struct is a nested type (Circle::Config) declared in the plugin's public header so the host can name it.
• A plugin registered this way still answers create(key) with the default ctor — you do not lose the parameterless path.
• Using create(key) semantics on a plain REGISTER plugin then passing a config throws std::runtime_error — see Creator.