Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
316 views
in Technique[技术] by (71.8m points)

c++ - How to prevent an object being created on the heap?

Does anyone know how I can, in platform-independent C++ code prevent an object from being created on the heap? That is, for a class "Foo", I want to prevent users from doing this:

Foo *ptr = new Foo;

and only allow them to do this:

Foo myfooObject;

Does anyone have any ideas?

Cheers,

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

Nick's answer is a good starting point, but incomplete, as you actually need to overload:

private:
    void* operator new(size_t);          // standard new
    void* operator new(size_t, void*);   // placement new
    void* operator new[](size_t);        // array new
    void* operator new[](size_t, void*); // placement array new

(Good coding practice would suggest you should also overload the delete and delete[] operators -- I would, but since they're not going to get called it isn't really necessary.)

Pauldoo is also correct that this doesn't survive aggregating on Foo, although it does survive inheriting from Foo. You could do some template meta-programming magic to HELP prevent this, but it would not be immune to "evil users" and thus is probably not worth the complication. Documentation of how it should be used, and code review to ensure it is used properly, are the only ~100% way.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...