c++ - 尝试构建 muParser:错误:'std::basic_ostream 的显式实例化但没有可用的定义

Question

我试图在 mac 上构建 muParser，它一直有效，直到我将 XCode 升级到 4.4 并更新了 gcc。现在我得到以下代码行生成我不明白的错误:

mu::console() << _T(" \"") << val.GetAsString() << _T("\" ");

../muparser/src/muParserBase.cpp:1823:   instantiated from here
../muparser/src/muParserBase.cpp:1823: error: explicit instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]' but no definition available
../muparser/src/muParserBase.cpp: In instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]':
../muparser/src/muParserBase.cpp:1823:   instantiated from here
../muparser/src/muParserBase.cpp:1823: error: explicit instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]' but no definition available
../muparser/src/muParserBase.cpp: In instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]':
../muparser/src/muParserBase.cpp:1823:   instantiated from here
../muparser/src/muParserBase.cpp:1823: error: explicit instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]' but no definition available
../muparser/src/muParserBase.cpp: In instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]':
../muparser/src/muParserBase.cpp:1823:   instantiated from here
../muparser/src/muParserBase.cpp:1823: error: explicit instantiation of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]' but no definition available

mu::console() 定义为:

inline std::ostream& console()
{
  return std::cout;
}

_T 是 #define _T(x) x

和GetAsString

  const TString& GetAsString() const
  {
    return m_strTok;
  }

TString 是一个 std::string

导致问题的是对 GetAsString 的调用。知道如何解决吗？

Answer 1

将这两行添加到您的 .pro 文件中，错误就会消失:

QMAKE_CFLAGS_X86_64 += -mmacosx-version-min=10.7
QMAKE_CXXFLAGS_X86_64 = $$QMAKE_CFLAGS_X86_64