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.. _mpi_query_thread:
MPI_Query_thread
================
.. include_body
:ref:`MPI_Query_thread` |mdash| Returns the current level of thread support
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#include <mpi.h>
int MPI_Query_thread(int *provided)
Fortran Syntax
^^^^^^^^^^^^^^
.. code-block:: fortran
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_QUERY_THREAD(PROVIDED, IERROR)
INTEGER PROVIDED, IERROR
Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
USE mpi_f08
MPI_Query_thread(provided, ierror)
INTEGER, INTENT(OUT) :: provided
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
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 :ref:`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
------
.. include:: ./ERRORS.rst
.. seealso::
* :ref:`MPI_Init`
* :ref:`MPI_Init_thread`
|
