cout 과 ofstream 으로 동시 출력해주는 stream 을 정의하려면?

   5 #ifndef __LOGSTREAM_H__
   6 #define __LOGSTREAM_H__
   7 
   8 #include <streambuf>
   9 #include <fstream>
  10 
  11 namespace mylib {
  12 
  13     class logstreambuf : public std::streambuf
  14     {
  15         typedef std::char_traits<char>  traits_type;
  16         typedef traits_type::int_type   int_type;
  17 
  18         private:
  19             std::streambuf* sb1_;
  20             std::streambuf* sb2_;
  21             bool            sb2_en_;
  22 
  23         public:
  24             logstreambuf() : sb1_(NULL), sb2_(NULL) {}
  25             logstreambuf(std::streambuf* sb1, std::streambuf* sb2)
  26                 : sb1_(sb1), sb2_(sb2) {} 
  27                 
  28             void init(std::streambuf* sb1, std::streambuf* sb2)
  29             {
  30                 sb1_ = sb1;
  31                 sb2_ = sb2;
  32             }   
  33             
  34         protected:
  35             int_type overflow(int_type c)
  38             { 
  39                 if (!traits_type::eq_int_type(c, traits_type::eof())) {
  40                     c = sb1_->sputc(c); 
  41                     if (!traits_type::eq_int_type(c, traits_type::eof()))
  42                         c = sb2_->overflow(c); 
  43                     return c; 
  44                 }   
  45                 else
  46                     return traits_type::not_eof(c);
  47             }       
  48             
  49             int sync()
  50             { 
  49                 int rc = sb1_->sync();
  50                 if (rc != -1)
  51                     rc = sb2_->sync();
  52                 return rc;
  53             }
  54 
  55     }; // class logstreambuf
  56 
  57     class logstream : public std::ostream
  58     {
  59         private:
  60             std::ofstream   ofs_;
  61             logstreambuf    buf_;
  62 
  63         public:
  64             logstream() : std::ios(0), std::ostream(&buf_) {}
  65             logstream(char* filename) : std::ios(0), std::ostream(&buf_)
  66             {
  67                 buf_.init(ofs_.rdbuf(), std::cout.rdbuf());
  68                 open(filename);
  69             }
  70 
  71             void open(char* filename)
  72             {
  73                 ofs_.open(filename);
  74             }
  75 
  76     }; // class logstream
  77
  78 }; // namespace mylib
  79 

/usr/include/c++/4.2.1/streambuf: In member function ‘virtual int mylib::logstreambuf::overflow(int)’:
/usr/include/c++/4.2.1/streambuf:763: error: ‘typename _Traits::int_type std::basic_streambuf<_CharT, _Traits>::overflow(typename _Traits::int_type) [with _CharT = char, _Traits = std::char_traits<char>]’ is protected
../src/logstream.h:40: error: within this context
/usr/include/c++/4.2.1/streambuf: In member function ‘virtual int mylib::logstreambuf::sync()’:
/usr/include/c++/4.2.1/streambuf:623: error: ‘int std::basic_streambuf<_CharT, _Traits>::sync() [with _CharT = char, _Traits = std::char_traits<char>]’ is protected
../src/logstream.h:49: error: within this context
/usr/include/c++/4.2.1/streambuf:623: error: ‘int std::basic_streambuf<_CharT, _Traits>::sync() [with _CharT = char, _Traits = std::char_traits<char>]’ is protected
../src/logstream.h:51: error: within this context
../src/main.cpp: In function ‘int main(int, char**, char**)’:
../src/main.cpp:12: warning: deprecated conversion from string constant to ‘char*’
make: *** [../src/main.o] Error 1