[Boost-users] gzip_compressor cannot be flushed and closed properly

From: Mengda Wu (phdggg_at_[hidden])
Date: 2008-02-09 03:48:28

Hi,

   I have a code block trying to output a series of gzip files. I wish to
have all the files flushed after the block.
But the files can only be flushed after exiting the whole program.
The files still have zero size after I try to close them. I am using
std::vector to store all the pointers to boost filtering_ostream.
Can you help?

  //Open iostreams

  char filename[20];
  std::vector<boost::iostreams::filtering_ostream *> os_vector;
  for(i=0; i<4; i++)
  {
     sprintf(filename, "file_%d.gz", i );
     std::ofstream *of = new std::ofstream(filename, std::ios_base::binary);
     boost::iostreams::filtering_ostream* os = new
boost::iostreams::filtering_ostream;
     os->push(boost::iostreams::gzip_compressor());
     os->push(*of);
     os_vector->push_back(os);
  }

  //Output something
  for(i=0; i<4; i++)
  {
     boost::iostreams::filtering_ostream* os = os_vector[i];
     os<<"Output something here" << std::endl;
  }

  //Close streams
  for(i=0; i<4; i++)
  {
    boost::iostreams::filtering_ostream* os = os_vector[i];
    os->strict_sync();
    os->pop();
    os->reset();
  }

Thanks,
Mengda