Question

My Issue is the following:

Why can my program not re-attach to the shared memory map?

I do the following in my program(it might be easier to use the example from the boost page for you while this is only a small fragment from my program):

First time, initialize it:

m_sharedMemory = new managed_shared_memory(create_only, segmentName.c_str() , 1000000);
m_hashMap = m_sharedMemory->construct<MyHashMap>(segmentName.c_str())( 3, boost::hash<std::string>(), std::equal_to<std::string>() , m_sharedMemory->get_allocator<ValueType>());

Second time “Re-Attach”

m_sharedMemory = new managed_shared_memory(open_only, segmentName.c_str());
m_hashMap = m_sharedMemory->find<MyHashMap>(segmentName.c_str()).first;

My Issue here is ,if 2 items get inserted the .second call on the returned object from find will show “1” which is actually wrong, its supposed to show 2, after this if my program tries to find anything in the stored map the program crashes. Has somebody been doing this already.

If i do the same thing in the initial program run it is no problem to lookup values from the hash. This only occurs if the program was initialized and later the program is restarted and does the attach and tries to retrieve values formerly inserted.

Thanks for the help.

Boost Quick Ref Map Example

Answer 1

While i was talking to the “maker” of this library he told me that it will only be possible to use the map within the same process.