MPI_Query_thread(3)                Open MPI                MPI_Query_thread(3)



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 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




1.4.1                            Jan 14, 2010              MPI_Query_thread(3)
