Full merge from trunk at revision 41356 of entire boost-root tree.

[SVN r41370]

example/doc_managed_aligned_allocation.cpp

@@ -0,0 +1,69 @@
+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga 2006-2007. 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_aligned_allocation
+#include <boost/interprocess/managed_shared_memory.hpp>
+#include <cassert>
+
+int main()
+{
+   using namespace boost::interprocess;
+
+   //Managed memory segment that allocates portions of a shared memory
+   //segment with the default management algorithm
+   shared_memory_object::remove("MyManagedShm");
+
+   try{
+      managed_shared_memory managed_shm(create_only, "MyManagedShm", 65536);
+
+      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(((char*)ptr-(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(((char*)ptr-(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
+         (3*Alignment - managed_shared_memory::PayloadPerAllocation, Alignment);
+
+      //Check alignment
+      assert(((char*)ptr-(char*)0) % Alignment == 0);
+
+      //Deallocate it
+      managed_shm.deallocate(ptr);
+   }
+   catch(...){
+      shared_memory_object::remove("MyManagedShm");
+      throw;
+   }
+   shared_memory_object::remove("MyManagedShm");
+   return 0;
+}
+//]
+#include <boost/interprocess/detail/config_end.hpp>