/Src/Dependencies/Boost/boost/interprocess/anonymous_shared_memory.hpp

  1//////////////////////////////////////////////////////////////////////////////
  2//
  3// (C) Copyright Ion Gaztanaga 2005-2009. Distributed under the Boost
  4// Software License, Version 1.0. (See accompanying file
  5// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  6//
  7// See http://www.boost.org/libs/interprocess for documentation.
  8//
  9//////////////////////////////////////////////////////////////////////////////
 10
 11#ifndef BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP
 12#define BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP
 13
 14#include <boost/interprocess/detail/config_begin.hpp>
 15#include <boost/interprocess/detail/workaround.hpp>
 16#include <boost/interprocess/creation_tags.hpp>
 17#include <boost/interprocess/detail/move.hpp>
 18#include <boost/interprocess/interprocess_fwd.hpp>
 19#include <boost/interprocess/mapped_region.hpp>
 20#include <cstddef>
 21
 22#if (!defined(BOOST_INTERPROCESS_WINDOWS))
 23#  include <fcntl.h>        //open, O_CREAT, O_*... 
 24#  include <sys/mman.h>     //mmap
 25#  include <sys/stat.h>     //mode_t, S_IRWXG, S_IRWXO, S_IRWXU,
 26#else
 27#include <boost/interprocess/windows_shared_memory.hpp>
 28#endif
 29
 30
 31//!\file
 32//!Describes a function that creates anonymous shared memory that can be
 33//!shared between forked processes
 34
 35namespace boost {
 36namespace interprocess {
 37
 38/// @cond
 39
 40namespace detail{
 41
 42   class raw_mapped_region_creator
 43   {
 44      public:
 45      static mapped_region
 46         create_posix_mapped_region(void *address, offset_t offset, std::size_t size)
 47      {
 48         mapped_region region;
 49         region.m_base = address;
 50         region.m_offset = offset;
 51         region.m_extra_offset = 0;
 52         region.m_size = size;
 53         return region;
 54      }
 55   };
 56}
 57
 58/// @endcond
 59
 60//!A function that creates an anonymous shared memory segment of size "size".
 61//!If "address" is passed the function will try to map the segment in that address.
 62//!Otherwise the operating system will choose the mapping address.
 63//!The function returns a mapped_region holding that segment or throws
 64//!interprocess_exception if the function fails.
 65//static mapped_region
 66static mapped_region
 67anonymous_shared_memory(std::size_t size, void *address = 0)
 68#if (!defined(BOOST_INTERPROCESS_WINDOWS))
 69{
 70   int flags;
 71   int fd = -1;
 72
 73   #if defined(MAP_ANONYMOUS) //Use MAP_ANONYMOUS
 74   flags = MAP_ANONYMOUS | MAP_SHARED;
 75   #elif !defined(MAP_ANONYMOUS) && defined(MAP_ANON) //use MAP_ANON
 76   flags = MAP_ANON | MAP_SHARED;
 77   #else // Use "/dev/zero"
 78   fd = open("/dev/zero", O_RDWR);
 79   flags = MAP_SHARED;
 80   if(fd == -1){
 81      error_info err = system_error_code();
 82      throw interprocess_exception(err);
 83   }
 84   #endif
 85
 86
 87   address = mmap( address
 88                  , size
 89                  , PROT_READ|PROT_WRITE
 90                  , flags
 91                  , fd
 92                  , 0);
 93
 94   if(address == MAP_FAILED){
 95      if(fd != -1)   
 96         close(fd);
 97      error_info err = system_error_code();
 98      throw interprocess_exception(err);
 99   }
100
101   if(fd != -1)   
102      close(fd);
103
104   return detail::raw_mapped_region_creator::create_posix_mapped_region(address, 0, size);
105}
106#else
107{
108   windows_shared_memory anonymous_mapping(create_only, 0, read_write, size);
109   return mapped_region(anonymous_mapping, read_write, 0, size, address);
110}
111
112#endif
113
114}  //namespace interprocess {
115}  //namespace boost {
116
117#include <boost/interprocess/detail/config_end.hpp>
118
119#endif   //BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP