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       MPI_Type_create_f90_integer - Returns a bounded MPI integer datatype


C Syntax

       #include <mpi.h>
       int MPI_Type_create_f90_integer(int r, MPI_Datatype *newtype)

Fortran Syntax

       INCLUDE ’mpif.h’

C++ Syntax

       #include <mpi.h>
       static MPI::Datatype MPI::Datatype::Create_f90_integer(int r)


       r         Precision, in decimal digits (integer).


       newtype   New data type (handle).

       IERROR    Fortran only: Error status (integer).


       This  function provides a way to declare KIND-parameterized INTEGER MPI
       datatypes. The argument is interpreted in a similar fashion to the  F90
       function  SELECTED_INT_KIND: r must be a scalar integer, and represents
       the desired level of numerical precision, in decimal digits.


       It is erroneous to supply a value for r not supported by the  compiler.

       The  Fortran function SELECTED_INT_KIND maps a large number of r values
       to a much smaller number of KIND parameters supported by the  compiler.
       KIND parameters are not specified by the language and are not portable.
       From the point of view of the language, variables of the same base type
       and  KIND  parameter are equivalent, even if their KIND parameters were
       generated by different r arguments to  SELECTED_INT_KIND.  However,  to
       help   facilitate  interoperability  in  a  heterogeneous  environment,
       equivalency  is  more  strictly  defined  for  datatypes  returned   by
       MPI_Type_create_f90_integer.  Two MPI datatypes, each generated by this
       function, will match if and only if they have identical values for r.

       The interaction between the datatypes returned by this function and the
       external32   data   representation   -   used   by   MPI_Pack_external,
       MPI_Unpack_external and  many  MPI_File  functions  -  is  subtle.  The
       external32 representation of returned datatypes is as follows.

            if (r > 38):
                 external32 size = n/a (undefined)
            else if (r > 18):
                 external32 size = 16
            else if (r > 9):
                 external32 size = 8
            else if (r > 4):
                 external32 size = 4
            else if (r > 2):
                 external32 size = 2
                 external32 size = 1

       If the external32 representation of a datatype is undefined, so are the
       results  of  using  that  datatype  in  operations  that  require   the
       external32  format.  Care  should  be  taken  not  to  use incompatible
       datatypes indirectly, e.g., as part of another datatype  or  through  a
       duplicated datatype, in these functions.

       If  a  variable is declared specifying a nondefault KIND value that was
       not obtained with SELECTED_INT_KIND (i.e., r is unknown), the only  way
       to  obtain  a  matching MPI datatype is to use the functions MPI_Sizeof
       and MPI_Type_match_size.


       Almost all MPI routines return an error value; C routines as the  value
       of  the  function  and  Fortran  routines  in  the  last  argument. C++
       functions do not return errors. If the default error handler is set  to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before the error value is returned, the current MPI  error  handler  is
       called.  By  default, this error handler aborts the MPI job, except for
       I/O  function  errors.  The  error  handler   may   be   changed   with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN
       may be used to cause error values to be returned. Note  that  MPI  does
       not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.