c++ - Calling a non-virtual function in derived class using a base class pointer -

as noted in this answer:

high reliance on dynamic_cast indication design has gone wrong.

what i'd know how can call custom function in derived class, there no same-name function in base class, using base class pointer , perhaps without dynamic_cast if in fact there better way.

if function virtual function defined in both, that's easy. unique function in derived class.

perhaps dynamic_cast best way afterall?

in order call function of derived class have obtain pointer derived class. option (depending on situation) may want using static_cast instead of dynamic, said:

it indication design has gone wrong

also, sometimes think it's ok use casts. when designing gui library game has base class widget , lots of subclasses. actual window layout made in editor , later loader class inflating layout. in order fill widgets layout actual specific each widget data (game related) made method quering widget's child widget. function retuned widget* , dynamic_casted actual type. have not found better design this.

later found gui system on android works same way