| ////////////////////////////////////////////////////////////////////////////// |
| // |
| // (C) Copyright Ion Gaztanaga 2006-2009. 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. |
| // |
| ////////////////////////////////////////////////////////////////////////////// |
| #include <boost/interprocess/detail/config_begin.hpp> |
| //[doc_managed_allocation_command |
| #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; |
| |
| //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(), 10000*sizeof(std::size_t)); |
| #else |
| //-> |
| managed_shared_memory managed_shm(create_only, "MySharedMemory", 10000*sizeof(std::size_t)); |
| //<- |
| #endif |
| //-> |
| |
| //Allocate at least 100 bytes, 1000 bytes if possible |
| std::size_t received_size, min_size = 100, preferred_size = 1000; |
| std::size_t *ptr = managed_shm.allocation_command<std::size_t> |
| (boost::interprocess::allocate_new, min_size, preferred_size, received_size).first; |
| |
| //Received size must be bigger than min_size |
| assert(received_size >= min_size); |
| |
| //Get free memory |
| std::size_t free_memory_after_allocation = managed_shm.get_free_memory(); |
| |
| //Now write the data |
| for(std::size_t i = 0; i < received_size; ++i) ptr[i] = i; |
| |
| //Now try to triplicate the buffer. We won't admit an expansion |
| //lower to the double of the original buffer. |
| //This "should" be successful since no other class is allocating |
| //memory from the segment |
| std::size_t expanded_size; |
| std::pair<std::size_t *, bool> ret = managed_shm.allocation_command |
| (boost::interprocess::expand_fwd, received_size*2, received_size*3, expanded_size, ptr); |
| |
| //Check invariants |
| assert(ret.second == true); |
| assert(ret.first == ptr); |
| assert(expanded_size >= received_size*2); |
| |
| //Get free memory and compare |
| std::size_t free_memory_after_expansion = managed_shm.get_free_memory(); |
| assert(free_memory_after_expansion < free_memory_after_allocation); |
| |
| //Write new values |
| for(std::size_t i = received_size; i < expanded_size; ++i) ptr[i] = i; |
| |
| //Try to shrink approximately to min_size, but the new size |
| //should be smaller than min_size*2. |
| //This "should" be successful since no other class is allocating |
| //memory from the segment |
| std::size_t shrunk_size; |
| ret = managed_shm.allocation_command |
| (boost::interprocess::shrink_in_place, min_size*2, min_size, shrunk_size, ptr); |
| |
| //Check invariants |
| assert(ret.second == true); |
| assert(ret.first == ptr); |
| assert(shrunk_size <= min_size*2); |
| assert(shrunk_size >= min_size); |
| |
| //Get free memory and compare |
| std::size_t free_memory_after_shrinking = managed_shm.get_free_memory(); |
| assert(free_memory_after_shrinking > free_memory_after_expansion); |
| |
| //Deallocate the buffer |
| managed_shm.deallocate(ptr); |
| return 0; |
| } |
| //] |
| #include <boost/interprocess/detail/config_end.hpp> |