NAME

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

SYNOPSIS

       int MPI_Query_thread(int *provided)

OUTPUT PARAMETERS

       provided
              - provided level of thread support (integer)

NOTES

       The valid values for the level of thread support are:
       MPI_THREAD_SINGLE
              - Only one thread will execute.
       MPI_THREAD_FUNNELED
              -  The  process may be multi-threaded, but only the main thread will make MPI calls
              (all MPI calls are funneled to the main thread).
       MPI_THREAD_SERIALIZED
              - 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).
       MPI_THREAD_MULTIPLE
              - 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.

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.

NOTES FOR FORTRAN

       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.

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_ERR_ARG
              -  Invalid  argument.  Some argument is invalid and is not identified by a specific
              error class (e.g., MPI_ERR_RANK ).
       MPI_ERR_OTHER
              - Other error; use MPI_Error_string to get more information about this error code.

                                            2/22/2022                         MPI_Query_thread(3)