.\" -*- nroff -*-
.\" Copyright 2013 Los Alamos National Security, LLC. All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" Copyright (c) 2010 Cisco Systems, Inc.  All rights reserved.
.\" $COPYRIGHT$
.TH MPI_T_cvar_handle_alloc 3 "May 26, 2022" "4.1.4" "Open MPI"
.
.SH NAME
\fBMPI_T_cvar_handle_alloc\fP, \fBMPI_T_cvar_handle_free\fP \- Allocate/free contol variable handles
.
.SH SYNTAX
.ft R
.
.SH C Syntax
.nf
#include <mpi.h>
int MPI_T_cvar_handle_alloc(int \fIcvar_index\fP, void *\fIobj_handle\fP,
                            MPI_T_cvar_handle *\fIhandle\fP, int *\fIcount\fP)

int MPI_T_cvar_handle_free(MPI_T_cvar_handle *\fIhandle\fP)

.fi
.SH DESCRIPTION
.ft R
MPI_T_cvar_handle_alloc binds the control variable specified in \fIcvar_index\fP to the MPI
object specified in \fIobj_handle\fP. If MPI_T_cvar_get_info returns MPI_T_BIND_NO_OBJECT
as the binding of the variable the \fIobj_handle\fP argument is ignored. The number of
values represented by this control variable is returned in the \fIcount\fP parameter. If the
control variable represents a string then \fIcount\fP will be the maximum length of the
string.

MPI_T_cvar_handle_free frees a handle allocated by MPI_T_cvar_handle_alloc and sets the
\fIhandle\fP argument to MPI_T_CVAR_HANDLE_NULL.


.SH NOTES
.ft R
Open MPI does not currently support binding MPI objects to control variables so the
\fIobj_handle\fP argument is always ignored.


.SH ERRORS
.ft R
MPI_T_cvar_handle_alloc() will fail if:
.TP 1i
[MPI_T_ERR_NOT_INITIALIZED]
The MPI Tools interface not initialized
.TP 1i
[MPI_T_ERR_INVALID_INDEX]
The control variable index is invalid
.TP 1i
[MPI_T_ERR_OUT_OF_HANDLES]
No more handles available
.TP 1i
MPI_T_cvar_handle_free() will fail if:
.TP 1i
[MPI_T_ERR_NOT_INITIALIZED]
The MPI Tools interface not initialized
.TP 1i
[MPI_T_ERR_INVALID_HANDLE]
The handle is invalid


.SH SEE ALSO
.ft R
.nf
MPI_T_cvar_get_info