Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
MPI_Comm_size(3)		      MPI		      MPI_Comm_size(3)

NAME
       MPI_Comm_size  -	  Determines  the  size	of the group associated	with a
       communicator

SYNOPSIS
       int MPI_Comm_size( MPI_Comm comm, int *size )

INPUT PARAMETER
       comm   -	communicator (handle)

OUTPUT PARAMETER
       size   -	number of processes in the group of comm (integer)

NOTES
NULL HANDLES
       The MPI 1.1 specification, in the section on opaque objects, explicitly
       disallows freeing a null	communicator.  The text	from the standard is:
       A null handle argument is an erroneous IN argument in MPI calls,	unless an
       exception is explicitly stated in the text that defines the function. Such
       exception is allowed for	handles	to request objects in Wait and Test calls
       (sections Communication Completion and Multiple Completions ). Otherwise, a
       null handle can only be passed to a function that allocates a new object	and
       returns a reference to it in the	handle.

THREAD AND INTERRUPT SAFETY
       This  routine is	both thread- and interrupt-safe.  This means that this
       routine may safely be used by multiple threads and from within a	signal
       handler.

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 guarentee 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_COMM
	      -	 Invalid communicator.	A common error is to use a null	commu-
	      nicator in a call	(not even allowed in MPI_Comm_rank ).
       MPI_ERR_ARG
	      -	Invalid	argument.  Some	argument is invalid and	is not identi-
	      fied by a	specific error class (e.g., MPI_ERR_RANK ).

LOCATION
       src/mpi/comm/comm_size.c

				   9/20/2012		      MPI_Comm_size(3)

NAME | SYNOPSIS | INPUT PARAMETER | OUTPUT PARAMETER | NOTES | NULL HANDLES | THREAD AND INTERRUPT SAFETY | NOTES FOR FORTRAN | ERRORS | LOCATION

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=MPI_Comm_size&sektion=3&manpath=FreeBSD+12.1-RELEASE+and+Ports>

home | help