Can it be safe to keep a copy of an std::initializer_list? What is the rationale?

Question

In my environment, the std::initializer_list is implemented as a pointer to the first element, and a size. Still in my specific setup, I was able to observe tha

Answer 1

From the C++11 standard, 18.9 [support.initlist]:

² An object of type initializer_list provides access to an array of objects of type const E. [ Note: A pair of pointers or a pointer plus a length would be obvious representations for initializer_list. initializer_list is used to implement initializer lists as specified in 8.5.4. Copying an initializer list does not copy the underlying elements. — end note ]

It's like taking pointers to objects. You can also make the pointer outlive the object. If you want to do it "safely", take/store a vector of elements instead.

Copying the elements would make it expensive, and thus nobody would use it. The documentation available makes it very clear about what it does.

EDIT:

This is Stroustrup's proposal for initializer_list: N2100. Reading it might enlighten on its design decisions.