This section specifies the interaction between MPI calls and threads. The section lists minimal requirements for thread compliant MPI implementations and defines functions that can be used for initializing the thread environment. MPI may be implemented in environments where threads are not supported or perform poorly. Therefore, it is not required that all MPI implementations fulfill all the requirements specified in this section.
This section generally assumes a thread package similar to POSIX threads [29], but the syntax and semantics of thread calls are not specified here --- these are beyond the scope of this document.