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       MPI_Query_thread -  Return the level of thread support provided by the MPI library


       int MPI_Query_thread(int *provided)


              -  Level  of  thread support provided.  This is the same value that was returned in
              the provided argument in MPI_Init_thread .


       The valid values for the level of thread support are:
              - Only one thread will execute.
              - The process may be multi-threaded, but only the main thread will make  MPI  calls
              (all MPI calls are funneled to the main thread).
              -  The  process may be multi-threaded, and multiple threads may make MPI calls, but
              only one at a time: MPI calls are not made concurrently from two  distinct  threads
              (all MPI calls are serialized).
              - Multiple threads may call MPI, with no restrictions.

              If  MPI_Init was called instead of MPI_Init_thread , the level of thread support is
              defined by the implementation.  This routine allows you to find  out  the  provided
              level.   It  is also useful for library routines that discover that MPI has already
              been initialized and wish to determine what level of thread support is available.


       This routine is both thread- and interrupt-safe.  This means that this routine may  safely
       be used by multiple threads and from within a signal handler.


       All  MPI  routines  in  Fortran  (except  for MPI_WTIME and MPI_WTICK ) have an additional
       argument ierr at the end of the argument list.  ierr  is  an  integer  and  has  the  same
       meaning  as  the  return  value  of  the  routine  in  C.   In  Fortran,  MPI routines are
       subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.


       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.

              - No error; MPI routine completed successfully.

                                            11/21/2018                        MPI_Query_thread(3)