::source_location

struct source_location {

public:

    constexpr source_location(int line, const char* file, const char* function) noexcept
        : this_line(line), this_file(file), this_function(function) { }

    constexpr int line() const noexcept {
        return this_line;
    }

    constexpr const char* file() const noexcept {
        return this_file;
    }

    constexpr const char* function() const noexcept {
        return this_function;
    }

private:

    const int this_line;
    const char* const this_file;
    const char* const this_function;

};

#define SOURCE_LOCATION (::source_location(__LINE__, __FILE__, "outside a function"))
#define SOURCE_LOCATION_FN (::source_location(__LINE__, __FILE__, __func__))