所以我试图获得一些为
gcc编写的代码,以便在Visual Studio 2008上编译.我有一个问题,我已经缩小到这个：
class value_t
{
public:
typedef std::deque<value_t> sequence_t;
typedef sequence_t::iterator iterator;
};
此代码失败：
1>cpptest.cpp 1>c:\program files\microsoft visual studio 9.0\vc\include\deque(518) : error C2027: use of undefined type 'value_t' 1> c:\temp\cpptest\cpptest.cpp(10) : see declaration of 'value_t' 1> c:\temp\cpptest\cpptest.cpp(13) : see reference to class template instantiation 'std::deque<_Ty>' being compiled 1> with 1> [ 1> _Ty=value_t 1> ] 1>c:\program files\microsoft visual studio 9.0\vc\include\deque(518) : error C2027: use of undefined type 'value_t' 1> c:\temp\cpptest\cpptest.cpp(10) : see declaration of 'value_t'
但是当我用std :: vector尝试这个时,编译很好：
class value_t
{
public:
typedef std::vector<value_t> sequence_t;
typedef sequence_t::iterator iterator;
};
怎么了？我试过在我能想到的任何地方添加’typename’,但此时此刻我认为它只是Dinkumware STL中的一个错误.谁能解释发生了什么,和/或提供解决方案？谢谢.
解决方法
它未定义的行为.请参阅c.l.c .moderated上的
this链接
来自Daniel K的回答： –
the C++ standard (both C++03 and
C++0x) says that what you are trying
causes undefined behavIoUr,see
[lib.res.on.functions]/2:“In particular,the effects are undefined in the following cases: [..] — if an incomplete type (3.9) is used as a template argument when instantiating a template component.”
