Boost C++ Libraries: Ticket #3768: Incomplete documentation for type_traits::extent and type_traits::rank

anonymous — Tue, 15 Dec 2009 10:10:59 GMT

So what would you suggest?

Inherits: Class template extent inherits from integral_constant<std::size_t, >EXTENT(T,N)>, where EXTENT(T,N) is the number of elements in the N'th array dimention >of type T. If T is not an array type, or if N > rank<T>::value, or if the N'th array bound is >incomplete, then EXTENT(T,N) is zero."

This does not explain what this type_traits is about.

Really? Concise maybe, but how does "where EXTENT(T,N) is the number of elements in the N'th array dimention of type T" not precisely describe the traits behaviour?

John.

Wed, 16 Dec 2009 01:36:59 GMT

Replying to anonymous:

So what would you suggest?

Inherits: Class template extent inherits from integral_constant<std::size_t, >EXTENT(T,N)>, where EXTENT(T,N) is the number of elements in the N'th array dimention >of type T. If T is not an array type, or if N > rank<T>::value, or if the N'th array bound is >incomplete, then EXTENT(T,N) is zero."

This does not explain what this type_traits is about.

Really? Concise maybe, but how does "where EXTENT(T,N) is the number of elements in the N'th array dimention of type T" not precisely describe the traits behaviour?

John.

I know it is said that:

'EXTENT(T,N) is the number of elements in the N'th array dimention of type T'

but I am not really sure what this means ( forget the misspelling of 'dimention', I know it is really 'dimension' ). Does this mean that T must be a C-style array ? If T must be a C-style array, does this mean that if T is, for example 'int [4][7]' that EXTENT(T,1) is 7 ? Or is there something else in both these assumptions.

Perhaps the problem is mine and I am looking into the words 'array' and 'dimension' for something that is not there.

status changed; resolution set

John Maddock — Thu, 04 Feb 2010 17:11:56 GMT

status new → closed
resolution → fixed

(In [59472]) Clarify docs and add some more examples. Fixes #3768.