Can a factory method return 0 in case of an error?-CodePudding

I am studying a bit of code, which contains a factory method, if I am remembering my object orientation correctly.

The factory method and the related classes can be described by the following pseudo-C .

The class Actor is the base class for the various implementations of concrete actions or operations, which in turn are implemented as derived classes.

The factory method createActor receives arguments which are read from an input script, hence prior to calling a constructor some error checking is being done.

I noticed, that in all cases when an error is detected, I find a return 0 statement. This can obviously be done, since the code (not written by me) compiles and runs.

However, the factory method is supposed to return a pointer to an Actor-class. Is in this case return 0 simply an obscure way to return NULL? Maybe I am overthinking this.

class Actor
{
  class ActorVariantA : Actor
  {
  }
  // all other ActorVariants are omitted for brevity

  Actor* createActor(arguments)
  {
    if (errorCondition)
      return 0
    if (conditionA)
      return new ActorVariantA(arguments)
  }
}

I found a somewhat related question, which in turn led me to Stroustrup himself.

So, the answer to my question would be: sort-of, but don't do it.

CodePudding user response：

yes, you are overthinking this. It should really be return nullptr, but in this case return 0 is equivalent.