The unmarshaling process is local and has shared memory access with the marshaling process.
MSHCTX_NOSHAREDMEM
The unmarshaling process does not have shared memory access with the marshaling process.
MSHCTX_DIFFERENTMACHINE
The unmarshaling process is on a different computer. The marshaling code cannot assume that a particular piece of application code is installed on that computer.
MSHCTX_INPROC
The unmarshaling will be done in another apartment in the same process.