#include "mpi.h" int MPI_Type_free ( MPI_Datatype *datatype )
The MPI standard states that (in Opaque Objects)
MPI provides certain predefined opaque objects and predefined, static handles to these objects. Such objects may not be destroyed.
Thus, it is an error to free a predefined datatype. The same section makes it clear that it is an error to free a null datatype.
All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran.
All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Errhandler_set; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error.