I have a simplified version of a class that I named Printer for SO. The real version takes data of various types and writes them to a buffer. I also have a method that can give the compile time length of a CString called constexprStrlen:

#include <cstring>
#include <iostream>

inline constexpr int constexprStrlen(const char* const a_cstr) {
    int i = 0;
    while (a_cstr[i] != 0)
        ++i;
    return i;
}

class Printer final {
    void appendAll() {}

public:
    void append(const char* const a_cstr) {
        std::cout << a_cstr << " (length unknown)" << std::endl;
        if (!a_cstr)
            return;
        write(a_cstr, ::strlen(a_cstr));
    }

    void append(const char* const a_cstr, const int a_len) {
        std::cout << a_cstr << " " << a_len << std::endl;
        if (!a_cstr)
            return;
        write(a_cstr, a_len);
    }

    // These are not the actual signatures I use, all that matters for SO is
    // that there are other append methods besides the two above
    void append(bool     ) {} // Content not relevant for SO
    void append(int      ) {} // Content not relevant for SO
    void append(long long) {} // Content not relevant for SO
    void append(double   ) {} // Content not relevant for SO

    template <class TArg, class... TArgs>
    void appendAll(TArg&& a_arg, TArgs&&... a_args) {
        append(std::forward<TArg>(a_arg));
        appendAll(std::forward<TArgs>(a_args)...);
    }

    void write(const char* const a_cstr, const int a_len) {
        // Content not relevant for SO
    }
};

int main() {
    const char* const cstr1 = "abc";
    const char* const cstr2 = "def";

    Printer p;

    p.append(cstr1); // Length unknown
    p.append(cstr2, constexprStrlen(cstr2)); // Length compile time known

    p.appendAll(cstr1, cstr2); // Both length unknown

    return 0;
}

I can avoid using strlen by calling append(const char*, int) and passing the result of constexprStrlen. My question is if there is any way to introduce constexprStrlen into appendAll so that it uses that instead of strlen