NAME

       MPI_T_pvar_read -  Read the value of a performance variable

SYNOPSIS

       int MPI_T_pvar_read(MPI_T_pvar_session session, MPI_T_pvar_handle handle, void *buf)

INPUT PARAMETERS

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

OUTPUT PARAMETERS

       buf    - initial address of storage location for variable value (choice)

NOTES

       The  MPI_T_pvar_read()  call queries the value of the performance variable with the handle
       "handle" in the session identified by the parameter session and stores the result  in  the
       buffer  identified by the parameter buf. The user is responsible to ensure that the buffer
       is of the appropriate size to hold the entire value of the performance variable (based  on
       the   datatype   and   count   returned   by   the   corresponding   previous   calls   to
       MPI_T_pvar_get_info() and MPI_T_pvar_handle_alloc(), respectively).

       The constant MPI_T_PVAR_ALL_HANDLES cannot  be  used  as  an  argument  for  the  function
       MPI_T_pvar_read().

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  guarentee 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_NOT_INITIALIZED
              - The MPI tool information interface is not initialized.
       MPI_T_ERR_INVALID_SESSION
              - Session argument is not valid.
       MPI_T_ERR_INVALID_HANDLE
              - The handle is invalid.

                                            11/9/2015                          MPI_T_pvar_read(3)