Question

我试图在Mac上构建muParser，直到我将XCode升级到4.4更新了gcc。现在我得到以下代码行生成我不理解的错误：

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std::string

调用GetAsString会导致问题。知道怎么解决吗？

Answer 1

将这两行添加到.pro文件中，错误将消失：

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

Answer 2

看起来您正在链接错误的标准库或包含错误的C ++包含。您需要确保包含路径的c ++标头与要链接的标准库相匹配。

如果您发布构建文件，我可以帮助查看是否存在不匹配。

Answer 3

当我升级到XCode 4.4.x时，删除了命令行工具。在XCode中，我去了XCode＆gt;首选项，选择下载选项卡，然后重新下载“命令行工具”，然后开始重新运行。也许这也可以解决你的问题？

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

3 个答案: