MPI_Type_create_f90_integer(3)					     Open MPI					    MPI_Type_create_f90_integer(3)

NAME

       MPI_Type_create_f90_integer - Returns a bounded MPI integer datatype

SYNTAX

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

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_TYPE_CREATE_F90_INTEGER (R, NEWTYPE, IERROR)
	    INTEGER   R, NEWTYPE, IERROR

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

INPUT PARAMETER

       r	 Precision, in decimal digits (integer).

OUTPUT PARAMETERS

       newtype	 New data type (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       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.

NOTES

       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  com-
       piler.  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
	    else:
		 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 dupli-
       cated 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.

ERRORS

       Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
       tions 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.

SEE ALSO

       MPI_Pack_external
       MPI_Sizeof
       MPI_Type_match_size
       MPI_Unpack_external
       SELECTED_INT_KIND

1.4.5								   Feb 10, 2012 				    MPI_Type_create_f90_integer(3)