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MPI_Query_thread(3)		      MPI		   MPI_Query_thread(3)

NAME
       MPI_Query_thread	 -  Return the level of	thread support provided	by the
       MPI library

SYNOPSIS
       int MPI_Query_thread(int	*provided)

OUTPUT PARAMETERS
       provided
	      -	provided level of thread support (integer)

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
	      concurrently from	two distinct threads (all MPI calls are	 seri-
	      alized).
       MPI_THREAD_MULTIPLE
	      -	Multiple threads may call MPI, with no restrictions.

	      If MPI_Init was called instead of	MPI_Init_thread	, the level of
	      thread  support  is defined by the implementation.  This routine
	      allows you to find out the provided level.  It  is  also	useful
	      for  library  routines  that  discover that MPI has already been
	      initialized and wish to determine	what level of  thread  support
	      is available.

THREAD AND INTERRUPT SAFETY
       This  routine  is  thread-safe.	 This  means  that this	routine	may be
       safely used by multiple threads without the need	for any	 user-provided
       thread  locks.  However,	the routine is not interrupt safe.  Typically,
       this is due to the use of memory	allocation routines such as malloc  or
       other  non-MPICH	 runtime  routines  that are themselves	not interrupt-
       safe.

NOTES FOR FORTRAN
       All MPI routines	in Fortran (except for MPI_WTIME and MPI_WTICK )  have
       an  additional  argument	ierr at	the end	of the argument	list.  ierr is
       an integer and has the same meaning as the return value of the  routine
       in  C.	In Fortran, MPI	routines are subroutines, and are invoked with
       the call	statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm )	are of type INTEGER in
       Fortran.

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 com-
       municators),  MPI_File_set_errhandler  (for files), and MPI_Win_set_er-
       rhandler	(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 guarantee that an MPI program can continue past
       an error; however, MPI implementations will attempt to  continue	 when-
       ever possible.

       MPI_SUCCESS
	      -	No error; MPI routine completed	successfully.
       MPI_ERR_ARG
	      -	Invalid	argument.  Some	argument is invalid and	is not identi-
	      fied by a	specific error class (e.g., MPI_ERR_RANK ).
       MPI_ERR_OTHER
	      -	 Other	error;	use  MPI_Error_string  to get more information
	      about this error code.

				   2/3/2025		   MPI_Query_thread(3)

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