c++ - Function overloading for const char*, const char(&)[N] and std::string -

what want achieve have overloads of function work string literals , std::string, produce compile time error const char* parameters. following code want:

#include <iostream> #include <string>  void foo(const char *& str) = delete;  void foo(const std::string& str) {     std::cout << "in overload const std::string&     : " << str << std::endl; }  template<size_t n> void foo(const char (& str)[n]) {     std::cout << "in overload array " << n << " elements : " << str << std::endl; }     int main() {     const char* ptr = "ptr const";     const char* const c_ptr = "const ptr const";     const char arr[] = "const array";     std::string cppstr = "cpp string";      foo("string literal");     //foo(ptr); //<- compile time error     foo(c_ptr); //<- should produce error     foo(arr);   //<- ideally should produce error     foo(cppstr); } 

i'm not happy, compiles char array variable, think there no way around if want accept string literals (if there is, please tell me)

what avoid however, std::string overload accepts const char * const variables. unfortunately, can't declare deleted overload takes const char * const& parameter, because match string literal.

any idea, how can make foo(c_ptr) produce compile-time error without affecting other overloads?

this code needed (except array - literals arrays, can't separate them)

#include <cstddef> #include <string>  template <class t> void foo(const t* const & str) = delete;  void foo(const std::string& str);  template<std::size_t n> void foo(const char (& str)[n]);  int main() {     const char* ptr = "ptr const";     const char* const c_ptr = "const ptr const";     const char arr[] = "const array";     std::string cppstr = "cpp string";      foo("string literal");     //foo(ptr); //<- compile time error     // foo(c_ptr); //<- should produce error     foo(arr);   //<- ideally should produce error     foo(cppstr); }