All MPI names have an MPI_ prefix, and all characters are upper case. Programs should not declare variables or functions with names with the prefix, MPI_ or PMPI_, to avoid possible name collisions.
All MPI Fortran subroutines have a return code in the last argument. A few MPI operations are functions, which do not have the return code argument. The return code value for successful completion is MPI_SUCCESS. MPI_SUCCESS Other error codes are implementation dependent; see Chapter . return codes
Handles are represented in Fortran as INTEGERs. Binary-valued variables are of type LOGICAL.
Array arguments are indexed from one.
Unless explicitly stated, the MPI F77 binding is consistent with ANSI standard Fortran 77. There are several points where the MPI standard diverges from the ANSI Fortran 77 standard. These exceptions are consistent with common practice in the Fortran community. In particular:
Figure: An example of calling a routine with mismatched formal and actual arguments.
All MPI named constants can be used wherever an entity declared with the PARAMETER attribute can be used in Fortran. There is one exception to this rule: the MPI constant MPI_BOTTOM (section ) can only be MPI_BOTTOM used as a buffer argument.