References are not pointers that cannot be null. References are semantically very different to pointers. References have value assignment and comparison semantics; that is, assignment or comparison operations involving references read and write the referenced value. Pointers have (counterintuitively) reference assignment and comparison semantics; that is, assignment or comparison operations involving pointers read and write … Read more
We talked with people in the library working group in the standards committee. They wanted the array_view they are trying to get into the standard to be read only. For the core guidelines, we needed an abstraction that was read and write. To avoid a clash between the (potential) standards and the guidelines support library … Read more
This is checking for overflow. Lets look at auto foo = narrow<int>(std::numeric_limits<unsigned int>::max()) T will be int and U will be unsigned int. So T t = narrow_cast<T>(u); will give store -1 in t. When you cast that back in if (static_cast<U>(t) != u) the -1 will convert back to std::numeric_limits<unsigned int>::max() so the check … Read more
What is it? A span<T> is: A very lightweight abstraction of a contiguous sequence of values of type T somewhere in memory. Basically a struct { T * ptr; std::size_t length; } with a bunch of convenience methods. A non-owning type (i.e. a “reference-type” rather than a “value type”): It never allocates nor deallocates anything … Read more