尝试建立muParser：错误：显式实例化'std :: basic_ostream但没有可用的定义 [英] Trying to build muParser: error: explicit instantiation of 'std::basic_ostream but no definition available

问题描述

我试图在mac上构建muParser，它工作，直到我升级XCode到4.4更新gcc。现在我得到下面这行代码生成的错误，我不明白：

Im trying to build muParser on the mac, it worked until I upgraded XCode to 4.4 which updated gcc. Now I get the following line of code generating the error which I don't understand:

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 code> #define _T（x）x

_T is #define _T(x) x

和 GetAsString

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

TString std :: string

这是对GetAsString的调用导致的问题。任何想法如何解决它？

It is the call to GetAsString that causes the problem. Any idea how to fix it?

推荐答案

将这两行添加到.pro文件，错误将消失： p>

Add these two lines to your .pro file and the error will go away:

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

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