.TH MPI_Register_datarep 3 "11/10/2017" " " "MPI"

.SH NAME

MPI_Register_datarep \-  Register functions for user-defined data  representations 

.SH SYNOPSIS

.nf

int MPI_Register_datarep(ROMIO_CONST char *datarep,

                       MPI_Datarep_conversion_function *read_conversion_fn,

                       MPI_Datarep_conversion_function *write_conversion_fn,

                       MPI_Datarep_extent_function *dtype_file_extent_fn,

                       void *extra_state)

.fi

.SH INPUT PARAMETERS

.PD 0

.TP

.B datarep 

- data representation name (string)

.PD 1

.PD 0

.TP

.B read_conversion_fn 

- function invoked to convert from file representation to

native representation (function)

.PD 1

.PD 0

.TP

.B write_conversion_fn 

- function invoked to convert from native representation to

file representation (function)

.PD 1

.PD 0

.TP

.B dtype_file_extent_fn 

- function invoked to get the exted of a datatype as represented

in the file (function)

.PD 1

.PD 0

.TP

.B extra_state 

- pointer to extra state that is passed to each of the

three functions

.PD 1

.SH NOTES

This function allows the user to provide routines to convert data from

an external representation, used within a file, and the native representation,

used within the CPU.  There is one predefined data representation,

.I external32

\&.

Please consult the MPI-2 standard for details on this

function.

.SH NOTES FOR FORTRAN

All MPI routines in Fortran (except for 

.I MPI_WTIME

and 

.I MPI_WTICK

) have

an additional argument 

.I ierr

at the end of the argument list.  

.I ierr

is an integer and has the same meaning as the return value of the routine

in C.  In Fortran, MPI routines are subroutines, and are invoked with the

.I call

statement.

All MPI objects (e.g., 

.I MPI_Datatype

, 

.I MPI_Comm

) are of type 

.I INTEGER

in Fortran.