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MPI_Query_thread(3OpenMPI)                                                        MPI_Query_thread(3OpenMPI)



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
       INCLUDE 'mpif.h'
       MPI_QUERY_THREAD(PROVIDED, IERROR)
            INTEGER   PROVIDED, 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 multi-threaded multithreaded
       threaded 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




Open MPI 1.2                                   September 2006                     MPI_Query_thread(3OpenMPI)