cpp/container/mdspan/mdspan

Construct an.

@1@ Construct an empty mdspan. Value-initializes, , and.
 * The behavior is undefined if is not an accessible range of  and  for the values of  and  after the invocation of this constructor.

@2@ Construct an mdspan over the underlying data referred by with extents represented by. Value-initializes, direct-non-list-initializes with  and  with.
 * The behavior is undefined if is not an accessible range of  and  for the values of  and  after the invocation of this constructor.
 * Let be.

@3,4@ Construct an mdspan over the underlying data referred by with extents represented by pack. Value-initializes, direct-non-list-initializes with  and  with.
 * The behavior is undefined if is not an accessible range of  and  for the values of  and  after the invocation of this constructor.

@5@ Construct an mdspan over the underlying data referred by with extents represented by. Value-initializes, direct-non-list-initializes with  and  with.
 * The behavior is undefined if is not an accessible range of  and  for the values of  and  after the invocation of this constructor.

@6@ Construct an mdspan over the underlying data referred by with layout mapping. Value-initializes, direct-non-list-initializes with  and  with.
 * The behavior is undefined if is not an accessible range of  and  for the values of  after the invocation of this constructor.

@7@ Construct an mdspan over the underlying data referred by with layout mapping  and accessor. Direct-non-list-initializes with,  with  and  with.
 * The behavior is undefined if is not an accessible range of  and  after the invocation of this constructor.

@8@ Converting constructor from another mdspan. Direct-non-list-initializes with,  with  and  with.
 * The behavior is undefined if :
 * is not an accessible range of and  for the values of  and  after the invocation of this constructor, or
 * for each rank index of,  is.


 * The program is ill-formed if:
 * is, or
 * is.


 * The expression inside is equivalent to:

@9@ Defaulted copy constructor.

@10@ Defaulted move constructor.