Hi , I need to design a data structure to transfer data between nodes by boost.MPI. Some elements of the the structure has dynamic size. For example, typedef struct{ double data1;vector<double> dataVec; } myDataType; The size of the dataVec depends on some intermidiate computing results. If I only declear it as the above myDataType, I think, only a pointer is transfered. When the data receiver try to access the elements of vector<double> dataVec, it got segmentation fault error. But, I also need to use the myDataType to declear other data structures. such as vector<myDataType> newDataVec; I cannot declear myDataType in a function , sucjh as main(), I got errors: main.cpp:200: error: main(int, char**)::myDataType; uses local type main(int, char**)::myDataType; Any help is really appreciated. thanks Jack Oct. 19 2010