std::meta::variable_of - cppreference.com

consteval std::meta::info variable_of( std::meta::info r );

Given a reflection r that represents a function parameter, returns a reflection that represents the corresponding variable in the function definition.

Parameter value

Return value

A reflection that represents a variable, which corresponds to the function parameter represented by r.

Exceptions

Throws std::meta::exception unless:

• r represents a parameter of a function F, and
• the call to variable_of is part of the evaluation of F's function body.

Example

#include <meta>
#include <print>

void f(int int_arg)
{
    constexpr auto rp = std::meta::parameters_of(^^f)[0];
    // const int& x = [:rp:];  // error: cannot splice the reflection of a parameter
    const int& x = [:std::meta::variable_of(rp):]; // OK, x refers to int_arg

    std::println("{}", x);
}

int main()
{
    f(42);
}

See also