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