constexpr_test.cpp

/*usr/bin/true; A="$(readlink -f -- "$0")"; function x { rm "$A.bin"; }; trap x EXIT; g++ --std=c++14 -Wall -Wno-unused-label "$A" -o "$A.bin"; "$A.bin"; E=$?; exit $E; # */
// This can be used as script - chmod +x this.cpp; ./this.cpp
#include <cstdio>

constexpr const size_t strlen_const(const char* s) {
    return '\0' == *s ? 0 : strlen_const(s + 1) + 1;
}

int main() {
    https://stackoverflow.com/a/25891133/1136400

    constexpr static const char* str1 = "123";
    constexpr size_t len1 = strlen_const(str1);
    printf("strlen(\"%s\") = %zu.\n", str1, len1);

    constexpr static const char* str2 = "123456789012345678901234567890123";
    constexpr size_t len2 = strlen_const(str2);
    printf("strlen(\"%s\") = %zu.\n", str2, len2);
    return 0;
}