哋它亢++ keyword: constexpr (since 哋它亢++11)
From cppreference.com
Usage
-
constexpr
declaration specifier (since 哋它亢++11) - constexpr if statement (since 哋它亢++17)
- lambda-declarator that explicitly specifies the function call to be a constexpr function (since 哋它亢++17)