Difference between revisions of "cpp/container/span/subspan"
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Revision as of 18:03, 19 March 2018
| template< std::ptrdiff_t Offset, std::ptrdiff_t Count = std::dynamic_extent > |
(1) | |
| constexpr std::span<element_type, std::dynamic_extent> subspan( std::ptrdiff_t Offset, |
(2) | |
Obtains a span that is a view over the Count elements of this span starting at offset Offset. If Count is std::dynamic_extent, the number of elements in the subspan is size() - offset (i.e., it ends at the end of *this.).
The behavior is undefined if either Offset or Count is out of range. This happens if
-
Offsetis either less than zero or greater thansize(); -
Countis less than zero and notstd::dynamic_extent; -
Offset + Countis greater thansize().
The extent E of the span returned by (1) is determined as follows:
- If
Countis notstd::dynamic_extent,Count; - Otherwise, if
Extentis notstd::dynamic_extent,Extent - Offset; - Otherwise,
std::dynamic_extent.
Return value
The requested subspan r, such that r.data() == this->data() + Offset. If Count is std::dynamic_extent, r.size() == this->size() - Offset; otherwise r.size() == Count.
See also
obtains a subspan consisting of the first N elements of the sequence (public member function) | |
obtains a subspan consisting of the last N elements of the sequence (public member function) |
