问题
i need to place a STL map in shared memory. Also have multiple process access that map. Any pointers to how it is done ?
I have checked this link. But need a more simpler method. Map in Shared memory
回答1:
For this to work you need to use a custom allocator that will allocate from the shared memory region, so that the map nodes are all in shared memory, and so that the pointer type of the allocator is not just a raw pointer but can refer to the shared memory region when it is mapped to different addresses in different processes.
You also need your std::map implementation to correctly use the allocator's pointer type everywhere it needs to use a pointer, and this isn't guaranteed by the standard.
The simplest way to do this currently is to use Boost.Interprocess which provides a nice API for shared memory and also provides allocators and containers that work correctly with it.
来源：https://stackoverflow.com/questions/35222065/c-stl-map-in-shared-memory