Thread: constructor for POD types?

Thanks CornedBee,


I quote your below two statements here.

1. "For PODs, zero-initialize."

2. "T t;: For non-primitives, default-initialize. For primitives, don't initialize at all."

Are they conflicting with each other for POD type? (I assume when you talks about primitive, you mean POD types.)

For normal understanding, T t should invoke constructor (default constructor), you mean for POD type, default constructor is not invoked so the value is un-initialized?

If yes, does any Spec covers T t does not make zero-initialization for POD type?

Originally Posted by CornedBee

8.5 is the relevant standard section. I was inaccurate in my wording above. The accurate but simplified version is this:

default-initialization: For non-PODs, call the default constructor (if any). For PODs, zero-initialize.

zero-initialize: For simple variables, set to 0. For aggregates, recursively zero-initialize all members. For non-PODs, set the underlying storage to all 0s.

T(): Default-initialize.

T t;: For non-primitives, default-initialize. For primitives, don't initialize at all.

Note: T t(); declares a function.

In addition, all static duration variables (globals, class statics, function statics) are zero-initialized before anything else is done.

Does that clear everything up?

regards,
George