The problem with files with improved memory: they go to disk instead of RAM

Question

I am trying to understand how Boost memory-bound files work. The following code works, it does what it should do, but the problem is that the file it creates is stored on disk (in the same directory of the executable file) instead of memory. Maybe there is a flag somewhere, but I could not find it ...
Thank you in advance for any information!

    #include <iostream>
    #include <string>
    #include <cstring>
    #include <boost/iostreams/device/mapped_file.hpp>
    using std::cout;
    using std::endl;

    int main(int argc, char** argv) {
     const int blockSize = 64;
     bool writer = false;

     if(argc > 1) {
      if(!strcmp(argv[1], "w"))
       writer = true;
     }

     boost::iostreams::mapped_file_params  params;
     params.path = "map.dat";
    // params.length = 1024;     // default: all the file
     params.new_file_size = blockSize;

     if(writer) {
      cout << "Writer" << endl;
      params.mode = std::ios_base::out;
     }
     else {
      cout << "Reader" << endl;
      params.mode = std::ios_base::in;
     }

        boost::iostreams::mapped_file  mf;
        mf.open(params);

     if(writer)
     {
      char *block = mf.data();
      strcpy(block, "Test data block...\0");
      cout << "Written: " << block << endl;
     }
     else
     {
      cout << "Reading: " << mf.const_data() << endl;
     }

     mf.close();

        return 0;
    }
/*
    Compiler options: -Wall -I$(PATH_BOOST_INCLUDE) -ggdb
    Linker options: -L$(PATH_BOOST_LIBS) -lboost_iostreams-mt -lboost_system-mt -lboost_filesystem-mt -DBOOST_FILESYSTEM_NO_DEPRECATED
*/

Used compiler: gcc 4.2.1
Boost 1.41.0
OS: MacOS X 10.6.2

Answer 1

Memory Mapping maps disk files to memory. To do this, there must be a file on disk!

: , - . http://www.boost.org/doc/libs/1_41_0/doc/html/interprocess/quick_guide.html

Answer 2

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