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MPI_Query_thread(3) man page (version 1.3.4)

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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  restric-
                               tions.

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++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       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

1.3.4                            Nov 11, 2009              MPI_Query_thread(3)

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