NAME

       MPI_T_pvar_start -  Start a performance variable

SYNOPSIS

       int MPI_T_pvar_start(MPI_T_pvar_session session, MPI_T_pvar_handle handle)

INPUT PARAMETERS

       session
              - identifier of performance experiment session (handle)
       handle - handle of a performance variable (handle)

NOTES

       If  the  constant  MPI_T_PVAR_ALL_HANDLES  is  passed  in  handle,  the MPI implementation
       attempts to start all variables within the session identified by the parameter session for
       which  handles  have  been allocated. In this case, the routine returns MPI_SUCCESS if all
       variables are started successfully,  otherwise  MPI_T_ERR_PVAR_NO_STARTSTOP  is  returned.
       Continuous   variables   and   variables   that  are  already  started  are  ignored  when
       MPI_T_PVAR_ALL_HANDLES is specified.

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
       malloc or other non-MPICH runtime routines that are themselves not interrupt-safe.

ERRORS

       All  MPI  routines  (except MPI_Wtime and 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  MPI_Comm_set_errhandler  (for
       communicators),  MPI_File_set_errhandler  (for files), and MPI_Win_set_errhandler (for RMA
       windows).  The MPI-1 routine MPI_Errhandler_set may be used but  its  use  is  deprecated.
       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; however, MPI implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.

       MPI_T_ERR_INVALID_HANDLE
              - The handle is invalid.
       MPI_T_ERR_INVALID_SESSION
              - Session argument is not valid.
       MPI_T_ERR_NOT_INITIALIZED
              - The MPI tool information interface is not initialized.
       MPI_T_ERR_PVAR_NO_STARTSTOP
              - The performance variable can not be started or stopped.
       MPI_ERR_OTHER
              - Other error; use MPI_Error_string to get more information about this error code.

                                            2/22/2022                         MPI_T_pvar_start(3)