Can std::string Be Used in a Constant Expression in C ?

Can std::string Be Embodied in a Constant Expression?

In C 11, utilizing std::string within a constant expression poses challenges. However, C 20 provides a solution, albeit with the caveat that the std::string must be destructed before constant evaluation concludes.

C 20 Solution:

While the code snippet you provided will not compile, the following code will:

constexpr std::size_t n = std::string("hello, world").size();

C 17 Alternative: string_view

As an alternative, C 17 introduces string_view, a lightweight string-like object that serves as a non-owning reference to a sequence of char objects. Unlike std::string, string_view is immutable and does not require destruction. This makes it ideal for use in constant expressions:

constexpr std::string_view sv = "hello, world";

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