.\" -*- nroff -*-
.\" Copyright 2013 Los Alamos National Security, LLC. All rights reserved.
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" $COPYRIGHT$
.TH MPI_Rsend 3 "Sep 30, 2023" "4.1.6" "Open MPI"
.SH NAME
\fBMPI_Rsend\fP \- Ready send.

.SH SYNTAX
.ft R
.SH C Syntax
.nf
#include <mpi.h>
int MPI_Rsend(const void *\fIbuf\fP, int\fI count\fP, MPI_Datatype\fI datatype\fP, int\fI dest\fP,
	int\fI tag\fP, MPI_Comm\fI comm\fP)

.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_RSEND(\fIBUF, COUNT, DATATYPE, DEST, TAG, COMM, IERROR\fP)
	<type>	\fIBUF\fP(*)
	INTEGER	\fICOUNT, DATATYPE, DEST, TAG, COMM, IERROR\fP

.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_Rsend(\fIbuf\fP, \fIcount\fP, \fIdatatype\fP, \fIdest\fP, \fItag\fP, \fIcomm\fP, \fIierror\fP)
	TYPE(*), DIMENSION(..), INTENT(IN) :: \fIbuf\fP
	INTEGER, INTENT(IN) :: \fIcount\fP, \fIdest\fP, \fItag\fP
	TYPE(MPI_Datatype), INTENT(IN) :: \fIdatatype\fP
	TYPE(MPI_Comm), INTENT(IN) :: \fIcomm\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH C++ Syntax
.nf
#include <mpi.h>
void Comm::Rsend(const void* \fIbuf\fP, int \fIcount\fP, const Datatype&
	\fIdatatype\fP, int \fIdest\fP, int \fItag\fP) const

.fi
.SH INPUT PARAMETERS
.ft R
.TP 1i
buf
Initial address of send buffer (choice).
.TP 1i
count
Number of elements in send buffer (nonnegative integer).
.TP 1i
datatype
Datatype of each send buffer element (handle).
.TP 1i
dest
Rank of destination (integer).
.TP 1i
tag
Message tag (integer).
.TP 1i
comm
Communicator (handle).

.SH OUTPUT PARAMETER
.ft R
.TP 1i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
A ready send may only be called if the user can guarantee that a receive is
already posted. It is an error if the receive is not posted before the
ready send is called.

.SH 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++ 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.
.sp
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.