cpp/utility/expected/value

@1,2@ If contains an expected value, returns the expected value (by copy), or nothing if  is (possibly cv-qualified).

@@ Otherwise, throws std containing the unexpected value contained in.

@@ If is, the program is ill-formed.

@3,4@ If contains an expected value, returns the expected value (by moving), or nothing if  is (possibly cv-qualified).

@@ Otherwise, throws std containing the unexpected value contained in.

@@ If or  is, the program is ill-formed.

Parameters
(none)

Return value
@1-4@ The expected value contained in.

Exceptions
@1,2@ Throws if  contain an unexpected value. @3,4@ Throws if  contain an unexpected value.