title: Error in a standard library when incllude own header
body: <p>I have a bytebuffer class, written in c++ by myself, i can compile it and it works as it should. Now i would like to use it in a big project, but when i include it in an another header, it throws an error if i try to build it. Here is the error:</p>
  
  <pre><code>  CXX    out.o
  In file included from /usr/include/c++/4.6/streambuf:808:0,
                   from /usr/include/c++/4.6/ios:44,
                   from /usr/include/c++/4.6/ostream:40,
                   from /usr/include/c++/4.6/iostream:40,
                   from /path/to/file/src/someheader1.h:29,
                   from /path/to/file/src/someheader2.h:31,
                   from /path/to/file/src/somesource.cpp:24:
  /usr/include/c++/4.6/bits/streambuf.tcc: In member function ‘virtual std::streamsize std::basic_streambuf&lt;_CharT, _Traits&gt;::xsgetn(std::basic_streambuf&lt;_CharT, _Traits&gt;::char_type*, std::streamsize)’:
  /usr/include/c++/4.6/bits/streambuf.tcc:56:38: error: expected unqualified-id before ‘(’ token
  /usr/include/c++/4.6/bits/streambuf.tcc: In member function ‘virtual std::streamsize std::basic_streambuf&lt;_CharT, _Traits&gt;::xsputn(const char_type*, std::streamsize)’:
  /usr/include/c++/4.6/bits/streambuf.tcc:90:38: error: expected unqualified-id before ‘(’ token
  In file included from /usr/include/c++/4.6/istream:859:0,
                   from /usr/include/c++/4.6/iostream:41,
                   from /path/to/file/src/someheader1.h:29,
                   from /path/to/file/src/someheader2.h:31,
                   from /path/to/file/src/somesource.cpp:24:
  /usr/include/c++/4.6/bits/istream.tcc: In member function ‘std::streamsize std::basic_istream&lt;_CharT, _Traits&gt;::readsome(std::basic_istream&lt;_CharT, _Traits&gt;::char_type*, std::streamsize)’:
  /usr/include/c++/4.6/bits/istream.tcc:693:46: error: expected unqualified-id before ‘(’ token
  make[4]: *** [out.o] Error 1
  </code></pre>
  
  <p>The skeleton of the header file in the project:</p>
  
  <pre><code>#ifndef _GUARD_
  #define _GUARD_
  
  #include &lt;string&gt;
  #include &lt;vector&gt;
  
  ...
  
  #include "bytebuffer.h"
  
  namespace A {
    namespace B {
  
      using namespace std;
      using namespace A::C;
  
      class Myclass {
      public: 
  
      ...
  
       virtual void save( ByteBuffer&amp; bb ) {
       }
  
       ...    
  
      } ;
    }
  }
  
  #endif  
  </code></pre>
  
  <p>The byte buffer is realy simple, it contains a vector for data, and put and get methods for different types. If i comment out the save method in the header, nothing changes, so i don't even have to declare a byte buffer, it throws the error. What could cause this?</p>