boost/interprocess/anonymous_shared_memory.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP
#define BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/interprocess/creation_tags.hpp>
#include <boost/move/move.hpp>
#include <boost/interprocess/interprocess_fwd.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <cstddef>
#if (!defined(BOOST_INTERPROCESS_WINDOWS))
# include <fcntl.h> //open, O_CREAT, O_*...
# include <sys/mman.h> //mmap
# include <sys/stat.h> //mode_t, S_IRWXG, S_IRWXO, S_IRWXU,
#else
#include <boost/interprocess/windows_shared_memory.hpp>
#endif
//!\file
//!Describes a function that creates anonymous shared memory that can be
//!shared between forked processes
namespace boost {
namespace interprocess {
/// @cond
namespace ipcdetail{
class raw_mapped_region_creator
{
public:
static mapped_region
create_posix_mapped_region(void *address, std::size_t size)
{
mapped_region region;
region.m_base = address;
region.m_size = size;
return region;
}
};
}
/// @endcond
//!A function that creates an anonymous shared memory segment of size "size".
//!If "address" is passed the function will try to map the segment in that address.
//!Otherwise the operating system will choose the mapping address.
//!The function returns a mapped_region holding that segment or throws
//!interprocess_exception if the function fails.
//static mapped_region
static mapped_region
anonymous_shared_memory(std::size_t size, void *address = 0)
#if (!defined(BOOST_INTERPROCESS_WINDOWS))
{
int flags;
int fd = -1;
#if defined(MAP_ANONYMOUS) //Use MAP_ANONYMOUS
flags = MAP_ANONYMOUS | MAP_SHARED;
#elif !defined(MAP_ANONYMOUS) && defined(MAP_ANON) //use MAP_ANON
flags = MAP_ANON | MAP_SHARED;
#else // Use "/dev/zero"
fd = open("/dev/zero", O_RDWR);
flags = MAP_SHARED;
if(fd == -1){
error_info err = system_error_code();
throw interprocess_exception(err);
}
#endif
address = mmap( address
, size
, PROT_READ|PROT_WRITE
, flags
, fd
, 0);
if(address == MAP_FAILED){
if(fd != -1)
close(fd);
error_info err = system_error_code();
throw interprocess_exception(err);
}
if(fd != -1)
close(fd);
return ipcdetail::raw_mapped_region_creator::create_posix_mapped_region(address, size);
}
#else
{
windows_shared_memory anonymous_mapping(create_only, 0, read_write, size);
return mapped_region(anonymous_mapping, read_write, 0, size, address);
}
#endif
} //namespace interprocess {
} //namespace boost {
#include <boost/interprocess/detail/config_end.hpp>
#endif //BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP