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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2006-2012. 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.
//
//////////////////////////////////////////////////////////////////////////////
//[doc_managed_aligned_allocation
#include <boost/interprocess/managed_shared_memory.hpp>
#include <cassert>
//<-
#include "../test/get_process_id_name.hpp"
//->
int main()
{
using namespace boost::interprocess;
//Remove shared memory on construction and destruction
struct shm_remove
{
//<-
#if 1
shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
#else
//->
shm_remove() { shared_memory_object::remove("MySharedMemory"); }
~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
//<-
#endif
//->
} remover;
//<-
(void)remover;
//->
//Managed memory segment that allocates portions of a shared memory
//segment with the default management algorithm
//<-
#if 1
managed_shared_memory managed_shm(create_only, test::get_process_id_name(), 65536);
#else
//->
managed_shared_memory managed_shm(create_only, "MySharedMemory", 65536);
//<-
#endif
//->
const std::size_t Alignment = 128;
//Allocate 100 bytes aligned to Alignment from segment, throwing version
void *ptr = managed_shm.allocate_aligned(100, Alignment);
//Check alignment
assert(std::size_t(static_cast<char*>(ptr)-static_cast<char*>(0)) % Alignment == 0);
//Deallocate it
managed_shm.deallocate(ptr);
//Non throwing version
ptr = managed_shm.allocate_aligned(100, Alignment, std::nothrow);
//Check alignment
assert(std::size_t(static_cast<char*>(ptr)-static_cast<char*>(0)) % Alignment == 0);
//Deallocate it
managed_shm.deallocate(ptr);
//If we want to efficiently allocate aligned blocks of memory
//use managed_shared_memory::PayloadPerAllocation value
assert(Alignment > managed_shared_memory::PayloadPerAllocation);
//This allocation will maximize the size of the aligned memory
//and will increase the possibility of finding more aligned memory
ptr = managed_shm.allocate_aligned
(3u*Alignment - managed_shared_memory::PayloadPerAllocation, Alignment);
//Check alignment
assert(std::size_t(static_cast<char*>(ptr)-static_cast<char*>(0)) % Alignment == 0);
//Deallocate it
managed_shm.deallocate(ptr);
return 0;
}
//]
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