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
415 views
in Technique[技术] by (71.8m points)

c++ - this is not a real pointer?

I am reading something about virtual table. When it comes to pointer __vptr, it is stated that by the author

Unlike the *this pointer, which is actually a function parameter used by the compiler to resolve self-references, *__vptr is a real pointer. Consequently, it makes each class object allocated bigger by the size of one pointer.

What does it mean here by saying this is actually a function parameter? And this is not a real pointer?

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)

Both pointers are real in the sense that they store an address of something else in memory. By "real" the author means "stored within the class", as opposed to this pointer, which is passed to member functions without being stored in the object itself. Essentially, the pointer to __vptr is part of the object, while this pointer is not.


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

...