mpi_query_thread(3openmpi) [osx man page]

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 multithreaded library, in  which	case  pro-
       vided 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++ func-
       tions 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)

MPI_Init_thread(3)							MPI							MPI_Init_thread(3)

NAME

       MPI_Init_thread -  Initialize the MPI execution environment

SYNOPSIS

       int MPI_Init_thread( int *argc, char ***argv, int required, int *provided )

INPUT PARAMETERS

       argc   - Pointer to the number of arguments
       argv   - Pointer to the argument vector
       required
	      - Level of desired thread support

OUTPUT PARAMETER

       provided
	      - Level of provided thread support

COMMAND LINE ARGUMENTS

       MPI  specifies  no  command-line arguments but does allow an MPI implementation to make use of them.  See MPI_INIT for a description of the
       command line arguments supported by MPI_INIT and MPI_INIT_THREAD .

NOTES

       The valid values for the level of thread support are:
       MPI_THREAD_SINGLE
	      - Only one thread will execute.
       MPI_THREAD_FUNNELED
	      - The process may be multi-threaded, but only the main thread will make MPI calls (all MPI calls are funneled to the main thread).
       MPI_THREAD_SERIALIZED
	      - The process may be multi-threaded, and multiple threads may make MPI calls, but only one at a time: MPI calls are not made concur-
	      rently from two distinct threads (all MPI calls are serialized).
       MPI_THREAD_MULTIPLE
	      - Multiple threads may call MPI, with no restrictions.

NOTES FOR FORTRAN

       Note that the Fortran binding for this routine does not have the argc and argv arguments. ( MPI_INIT_THREAD(required, provided, ierror) )

ERRORS

       All  MPI  routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the function and Fortran routines in
       the last argument.  Before the value is returned, the current MPI error handler is called.  By default, this error handler aborts  the  MPI
       job.   The  error  handler  may	be  changed  with  MPI_Comm_set_errhandler  (for  communicators), MPI_File_set_errhandler (for files), and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its  use  is  deprecated.   The	predefined
       error handler MPI_ERRORS_RETURN may be used to cause error values to be returned.  Note that MPI does not guarentee that an MPI program can
       continue past an error; however, MPI implementations will attempt to continue whenever possible.

       MPI_SUCCESS
	      - No error; MPI routine completed successfully.
       MPI_ERR_OTHER
	      - Other error; use MPI_Error_string to get more information about this error code.

SEE ALSO

       MPI_Init, MPI_Finalize

LOCATION

       initthread.c

								     6/18/2011							MPI_Init_thread(3)