MinGW 4.9 - why doesn't std::to_string and std::stoi work?

Question

C++ / C#

I tried -c++11, -c++14, still can't find it, although these functions are defined in basic_string.h in the compiler files (MinGW).
There is such a terrible macro:

#if ((__cplusplus >= 201103L) && defined(_GLIBCXX_USE_C99) \
     && !defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF))

How to make to_string and stoi connect?
A piece of code from basic_string.h, where to_string and stoi are defined:

spoiler

#if ((__cplusplus >= 201103L) && defined(_GLIBCXX_USE_C99) \
     && !defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF))

#include <ext/string_conversions.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // 21.4 Numeric Conversions [string.conversions].
  inline int
  stoi(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(),
          __idx, __base); }

  inline long
  stol(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
           __idx, __base); }

  inline unsigned long
  stoul(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
           __idx, __base); }

  inline long long
  stoll(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
           __idx, __base); }

  inline unsigned long long
  stoull(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
           __idx, __base); }

  // NB: strtof vs strtod.
  inline float
  stof(const string& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }

  inline double
  stod(const string& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }

  inline long double
  stold(const string& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }

  // NB: (v)snprintf vs sprintf.

  // DR 1261.
  inline string
  to_string(int __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(int),
             "%d", __val); }

  inline string
  to_string(unsigned __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
             4 * sizeof(unsigned),
             "%u", __val); }

  inline string
  to_string(long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(long),
             "%ld", __val); }

  inline string
  to_string(unsigned long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
             4 * sizeof(unsigned long),
             "%lu", __val); }

  inline string
  to_string(long long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
             4 * sizeof(long long),
             "%lld", __val); }

  inline string
  to_string(unsigned long long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
             4 * sizeof(unsigned long long),
             "%llu", __val); }

  inline string
  to_string(float __val)
  {
    const int __n = 
      __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
             "%f", __val);
  }

  inline string
  to_string(double __val)
  {
    const int __n = 
      __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
             "%f", __val);
  }

  inline string
  to_string(long double __val)
  {
    const int __n = 
      __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
             "%Lf", __val);
  }

#ifdef _GLIBCXX_USE_WCHAR_T
  inline int 
  stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),
          __idx, __base); }

  inline long 
  stol(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(),
           __idx, __base); }

  inline unsigned long
  stoul(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(),
           __idx, __base); }

  inline long long
  stoll(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(),
           __idx, __base); }

  inline unsigned long long
  stoull(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(),
           __idx, __base); }

  // NB: wcstof vs wcstod.
  inline float
  stof(const wstring& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); }

  inline double
  stod(const wstring& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); }

  inline long double
  stold(const wstring& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); }

  // DR 1261.
  inline wstring
  to_wstring(int __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(int),
              L"%d", __val); }

  inline wstring
  to_wstring(unsigned __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
              4 * sizeof(unsigned),
              L"%u", __val); }

  inline wstring
  to_wstring(long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long),
              L"%ld", __val); }

  inline wstring
  to_wstring(unsigned long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
              4 * sizeof(unsigned long),
              L"%lu", __val); }

  inline wstring
  to_wstring(long long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
              4 * sizeof(long long),
              L"%lld", __val); }

  inline wstring
  to_wstring(unsigned long long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
              4 * sizeof(unsigned long long),
              L"%llu", __val); }

  inline wstring
  to_wstring(float __val)
  {
    const int __n =
      __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
              L"%f", __val);
  }

  inline wstring
  to_wstring(double __val)
  {
    const int __n =
      __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
              L"%f", __val);
  }

  inline wstring
  to_wstring(long double __val)
  {
    const int __n =
      __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
              L"%Lf", __val);
  }
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* C++11 && _GLIBCXX_USE_C99 ... */

Answer 1

Which specific fork of MinGW did you install? Put the one in which these functions work. I recommend MinGW-w64