.\" -*- nroff -*-
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines
.\" $COPYRIGHT$
.TH MPI_Comm_set_info 3 "May 26, 2022" "4.1.4" "Open MPI"
.SH NAME
\fBMPI_Comm_set_info\fP \- Set communicator info hints
.
.SH SYNTAX
.ft R
.SH C Syntax
.nf
#include <mpi.h>
int MPI_Comm_set_info(MPI_Comm \fIcomm\fP, MPI_Info \fIinfo\fP)
.
.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_SET_INFO(\fICOMM, INFO, IERROR\fP)
	INTEGER	\fICOMM, INFO, IERROR \fP
.
.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_Comm_set_info(\fIcomm\fP, \fIinfo\fP, \fIierror\fP)
	TYPE(MPI_Comm), INTENT(IN) :: \fIcomm\fP
	TYPE(MPI_Info), INTENT(IN) :: \fIinfo\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH INPUT PARAMETERS
.ft R
.TP 1i
comm
Communicator on which to set info hints
.TP 1i
info
Info object containing hints to be set on
.I comm
.
.SH OUTPUT PARAMETERS
.TP 1i
IERROR
Fortran only: Error status (integer).
.
.SH DESCRIPTION
.ft R
MPI_COMM_SET_INFO sets new values for the hints of the communicator
associated with
.IR comm .
MPI_COMM_SET_INFO is a collective routine. The info object may be
different on each process, but any info entries that an implementation
requires to be the same on all processes must appear with the same
value in each process's
.I info
object.
.sp
The following info key assertions may be accepted by Open MPI:
.sp
\fImpi_assert_no_any_tag\fP (boolean): If set to true, then the
implementation may assume that the process will not use the
MPI_ANY_TAG wildcard on the given
communicator.
.sp
\fImpi_assert_no_any_source\fP (boolean): If set to true, then
the implementation may assume that the process will not use the
MPI_ANY_SOURCE wildcard on the given communicator.
.sp
\fImpi_assert_exact_length\fP (boolean): If set to true, then the
implementation may assume that the lengths of messages received by the
process are equal to the lengths of the corresponding receive buffers,
for point-to-point communication operations on the given communicator.
.sp
\fImpi_assert_allow_overtaking\fP (boolean): If set to true, then the
implementation may assume that point-to-point communications on the
given communicator do not rely on the non-overtaking rule specified in
MPI-3.1 Section 3.5. In other words, the application asserts that send
operations are not required to be matched at the receiver in the order
in which the send operations were performed by the sender, and receive
operations are not required to be matched in the order in which they
were performed by the receiver.
.
.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.
.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.
.
.SH SEE ALSO
MPI_Comm_get_info,
MPI_Info_create,
MPI_Info_set,
MPI_Info_free