This chapter begins with calls used to create generalized requests, which allow users to create new nonblocking operations with an interface similar to what is present in MPI. These calls can be used to layer new functionality on top of MPI. Next, Section Associating Information with Status deals with setting the information found in status. This functionality is needed for generalized requests.
The chapter continues, in Section MPI and Threads , with a discussion of how threads are to be handled in MPI. Although thread compliance is not required, the standard specifies how threads are to work if they are provided.