Q. Datatype Functions for Message Passing?

Datatype: It denotes type of data in message. This field is essential in the sense that MPI supports heterogeneous computing and different nodes can interpret count field differently. E.g. if the message comprise a strings of 2n characters (count=2n) a number of machines might interpret it having 2n characters and some having n characters depending on the storage allocated for every character (1 or 2). The basic datatype in MPI include all basic types in FORTRAN and C with two extra types which are MPI_BYTE and MPI_PACKED. MPI_BYTE denotes a byte of 8 bits.