Hello, I'd like to share a vector of vectors (jagged 2D array). The data come from a deserialization. I know the size of the "external" vector. The sizes of the "internal" vectors are discovered during deserialization. I read : http://www.boost.org/doc/libs/1_52_0/doc/html/interprocess/quick_guide.html#... and regarding this line : managed_shared_memory segment(create_only, "MySharedMemory", //segment name 65536); how to set the size (3rd argument), when considering my use case ? Even with a simple vector, and if the number and the types of the elements are know? i woldn't know what size to set for truncation. On VS 2010, a sizeof(vector<int>) is 40; I suppose I have to add it sizeof(int)*nbElements to get the full size. 1. I don't know if this assumption is valid 2. If so, I don't know if it's still valid when using Boost.Interprocess (I suppose it isn't) 3. I don't know how to generalize that to a vector of vectors in order what should be the truncation size. Thanks for help. PS : I also read http://www.boost.org/doc/libs/1_52_0/doc/html/interprocess/managed_memory_se..., but I havn't been enlightened about these points.