oracular (3) MPI_Query_thread.openmpi.3.gz

Provided by: openmpi-doc_4.1.6-13.3ubuntu2_all bug

NAME
       MPI_Query_thread - Returns the current level of thread support


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Query_thread(int *provided)


Fortran Syntax
       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_QUERY_THREAD(PROVIDED, IERROR)
            INTEGER   PROVIDED, IERROR


Fortran 2008 Syntax
       USE mpi_f08
       MPI_Query_thread(provided, ierror)
            INTEGER, INTENT(OUT) :: provided
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror


C++ Syntax
       #include <mpi.h>
       int MPI::Query_thread()


OUTPUT PARAMETERS
       provided  C/Fortran only: Level of thread support (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       This routine returns in provided the current level of thread support. If MPI was initialized by a call to
       MPI_Init_thread, provided will have the same value as was returned by that function.

       The possible values of provided are as follows:

       MPI_THREAD_SINGLE       Only one thread may execute.

       MPI_THREAD_FUNNELED     If the process is multithreaded, only the thread  that  called  MPI_Init[_thread]
                               may make MPI calls.

       MPI_THREAD_SERIALIZED   If  the  process  is multithreaded, only one thread may make MPI library calls at
                               one time.

       MPI_THREAD_MULTIPLE     If the process is multithreaded, multiple threads may call MPI at  once  with  no
                               restrictions.


NOTES
       In  Open  MPI,  provided  is  always  MPI_THREAD_SINGLE,  unless  the  program  has  been linked with the
       multithreaded library, in which case provided is MPI_THREAD_MULTIPLE.


ERRORS
       Almost all MPI routines return an error value; C routines as  the  value  of  the  function  and  Fortran
       routines in the last argument. C++ functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the  C++  exception  mechanism  will  be  used  to  throw  an
       MPI::Exception object.

       Before  the  error  value  is  returned,  the current MPI error handler is called. By default, this error
       handler aborts the MPI job, except for I/O function  errors.  The  error  handler  may  be  changed  with
       MPI_Comm_set_errhandler; 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.

       See the MPI man page for a full list of MPI error codes.


SEE ALSO
       MPI_Init
       MPI_Init_thread