C ++ std :: cout缓冲区重定向seg错误

Question

Hi So i wrote some simple code to redirect the std::cout output to a std::ostringstream and it works fine from within main eg.

#include <iostream>
#include <sstream>

int main(){
  std::ostringstream m_oss;
  std::streambuf *m_sbuf, *bcout;

  m_sbuf=m_oss.rdbuf();
  bcout = std::cout.rdbuf();
  std::cout.rdbuf(m_sbuf);

  std::cout<<"hello world"<<std::endl;

  std::cout.rdbuf(bcout);        // restore cout's original streambuf

  std::cout<<m_oss.str();

  return 0;
}

however if i want to do the same redirect within a class then I get a Seg fault on the line 'std::cout.rdbuf(m_sbuf);'

eg

#include <iostream>
#include <sstream>

class test {

  public:
     std::ostringstream m_oss;
     std::streambuf *m_sbuf, *bcout;

     test(){

        m_sbuf=m_oss.rdbuf();
        bcout = std::cout.rdbuf();
        std::cout.rdbuf(m_sbuf);
     }


     void print(){

       std::cout.rdbuf(bcout);        // restore cout's original streambuf
       std::cout<<m_oss.str();

     }

};

int main(){

  test t();

  std::cout<<"Hello world"<<std::endl;

  t.print();     

  return 0;
}

any ideas how i can encapsulate this in a class as i don't really want the end user to see it and get confused?

Answer 1

Use this to instantiate object t :

test t;

not

test t();