.\" -*- 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_pvar_start 3 "Dec 18, 2020" "4.1.0" "Open MPI"
.
.SH NAME
\fBMPI_T_pvar_start\fP, \fBMPI_T_pvar_stop\fP \- Start/stop a performance variable
.
.SH SYNTAX
.ft R
.
.SH C Syntax
.nf
#include <mpi.h>
int MPI_T_pvar_start(MPI_T_pvar_session \fIsession\fP, MPI_T_pvar_handle \fIhandle\fP)

int MPI_T_pvar_stop(MPI_T_pvar_session \fIsession\fP, MPI_T_pvar_handle \fIhandle\fP)

.fi
.SH INPUT PARAMETERS
.ft R
.TP 1i
session
Performance experiment session.
.TP 1i
handle
Performance variable handle.

.SH DESCRIPTION
.ft R
MPI_T_pvar_start starts the performance variable with the handle specified in \fIhandle\fP.
The special value MPI_T_PVAR_ALL_HANDLES can be passed in \fIhandle\fP to start all
non-continuous handles in the session specified in \fIsession\fP.

MPI_T_pvar_stop stops the performance variable with the handle specified in \fIhandle\fP.
The special value MPI_T_PVAR_ALL_HANDLES can be passed in \fIhandle\fP to stop all
non-continuous handles in the session specified in \fIsession\fP.

Continuous performance variables can neither be started nor stopped.

.SH ERRORS
.ft R
MPI_T_pvar_start() and MPI_T_pvar_stop() will fail if:
.TP 1i
[MPI_T_ERR_NOT_INITIALIZED]
The MPI Tools interface not initialized
.TP 1i
[MPI_T_ERR_INVALID_SESSION]
Session parameter is not a valid session
.TP 1i
[MPI_T_ERR_INVALID_HANDLE]
Invalid handle or handle not associated with the session
.TP 1i
[MPI_T_ERR_PVAR_NO_STARTSTOP]
The variable cannot be started or stopped

.SH SEE ALSO
.ft R
.nf
MPI_T_pvar_get_info