focal (3) MPI_Query_thread.3.gz

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

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

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 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.

                                                   11/12/2019                                MPI_Query_thread(3)