.TH MPI_COMM_DUP_FN 3 "6/24/2006" "LAM/MPI 7.1.4" "LAM/MPI"
.SH NAME
MPI_COMM_DUP_FN \-  Built-in MPI function to simple-mindedly copy communicator attributes. 
.SH SYNOPSIS
.nf
#include <mpi.h>
int MPI_COMM_DUP_FN(MPI_Comm comm, int key, void *extra, 
                   void *attrin, void *attrout, int *flag)
.fi
.SH INPUT PARAMETERS
.PD 0
.TP
.B comm 
- communicator (handle)
.PD 1
.PD 0
.TP
.B key 
- key value (integer)
.PD 1
.PD 0
.TP
.B extra 
- extra state
.PD 1
.PD 0
.TP
.B attrin 
- in value for attribute
.PD 1

.SH OUTPUT PARAMETERS
.PD 0
.TP
.B attrout 
- out value for attribute
.PD 1
.PD 0
.TP
.B flag 
- 1 if attribute copied successfully, 0 otherwise (logical)
.PD 1

.SH NOTES

This function blindly byte-copies attributes on communicators.  It is
the default atrribute-copying function for communicators.  This
function will always return 
.I MPI_SUCCESS
, and 
.I flag
will always be
set to 1.

The actual copy is performed by the code

.nf
*((void **) attrout) = attrin;
.fi


If this simple assignment is not sufficient for your attributes, you
will need to reassign the attribute-copying function on relevant
keyvals on communicators with the 
.I MPI_Comm_keyval_create
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.

.SH SEE ALSO
MPI_Comm_keyval_create
.br

.SH MORE INFORMATION

For more information, please see the official MPI Forum web site,
which contains the text of both the MPI-1 and MPI-2 standards.  These
documents contain detailed information about each MPI function (most
of which is not duplicated in these man pages).

.I http://www.mpi-forum.org/


.SH ACKNOWLEDGEMENTS

The LAM Team would like the thank the MPICH Team for the handy program
to generate man pages ("doctext" from
.I ftp://ftp.mcs.anl.gov/pub/sowing/sowing.tar.gz
), the initial
formatting, and some initial text for most of the MPI-1 man pages.
.SH LOCATION
dupfn.c