.TH MPI_T_pvar_readreset 3 "11/12/2019" " " "MPI"
.SH NAME
MPI_T_pvar_readreset \-  Read the value of a performance variable and then reset it 
.SH SYNOPSIS
.nf
int MPI_T_pvar_readreset(MPI_T_pvar_session session, MPI_T_pvar_handle handle, void *buf)
.fi
.SH INPUT PARAMETERS
.PD 0
.TP
.B session 
- identifier of performance experiment session (handle)
.PD 1
.PD 0
.TP
.B handle 
- handle of a performance variable (handle)
.PD 1

.SH OUTPUT PARAMETERS
.PD 0
.TP
.B buf 
- initial address of storage location for variable value (choice)
.PD 1

.SH THREAD AND INTERRUPT SAFETY

This routine is thread-safe.  This means that this routine may be
safely used by multiple threads without the need for any user-provided
thread locks.  However, the routine is not interrupt safe.  Typically,
this is due to the use of memory allocation routines such as 
.I malloc
or other non-MPICH runtime routines that are themselves not interrupt-safe.

.SH ERRORS

All MPI routines (except 
.I MPI_Wtime
and 
.I MPI_Wtick
) return an error value;
C routines as the value of the function and Fortran routines in the last
argument.  Before the value is returned, the current MPI error handler is
called.  By default, this error handler aborts the MPI job.  The error handler
may be changed with 
.I MPI_Comm_set_errhandler
(for communicators),
.I MPI_File_set_errhandler
(for files), and 
.I MPI_Win_set_errhandler
(for
RMA windows).  The MPI-1 routine 
.I MPI_Errhandler_set
may be used but
its use is deprecated.  The predefined error handler
.I MPI_ERRORS_RETURN
may be used to cause error values to be returned.
Note that MPI does 
.B not
guarentee that an MPI program can continue past
an error; however, MPI implementations will attempt to continue whenever
possible.

.PD 0
.TP
.B MPI_SUCCESS 
- No error; MPI routine completed successfully.
.PD 1
.PD 0
.TP
.B MPI_T_ERR_NOT_INITIALIZED 
- The MPI tool information interface is not initialized.
.PD 1
.PD 0
.TP
.B MPI_T_ERR_INVALID_SESSION 
- Session argument is not valid.
.PD 1
.PD 0
.TP
.B MPI_T_ERR_INVALID_HANDLE 
- The handle is invalid.
.PD 1
.PD 0
.TP
.B MPI_T_ERR_PVAR_NO_WRITE 
- The performance variable can not be written or reset.
.PD 1
.PD 0
.TP
.B MPI_T_ERR_PVAR_NO_ATOMIC 
- The performance variable can not be read/write atomically.
.PD 1