MPI_Win_create(3) LAM/MPI MPI_Win_create(3)
MPI_Win_create - Specifies an window accessible by remote processes
MPI_Win_create(void *base, MPI_Aint size, int disp_unit,
MPI_Info info, MPI_Comm comm, MPI_Win *newwin)
base - initial address of window (choice)
size - size of window in bytes (nonnegative integer)
- local unit size for displacements, in bytes (positive integer)
info - info argument (handle)
comm - communicator (handle)
newwin - window object returned by the call (handle)
Common choices for disp_unit are 1 (no scaling), and (in C syntax) sizeof(type), for a
window that consists of an array of elements of type type. The later choice will allow one
to use array indices in RMA calls, and have those scaled correctly to byte displacements,
even in a heterogeneous environment. ( End of advice to users.) The info argument pro-
vides optimization hints to the runtime about the expected usage pattern of the window.
The various processes in the group of comm may specify completely different target win-
dows, in location, size, displacement units and info arguments. As long as all the get,
put and accumulate accesses to a particular process fit their specific target window this
should pose no problem. The same area in memory may appear in multiple windows, each asso-
ciated with a different window object. However, concurrent communications to distinct,
overlapping windows may lead to erroneous results.
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argu-
ment 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.
USAGE WITH IMPI EXTENSIONS
The IMPI standard only supports MPI-1 functions. Hence, this function is currently not
designed to operate within an IMPI job.
If an error occurs in an MPI function, the current MPI error handler is called to handle
it. By default, this error handler aborts the MPI job. The error handler may be changed
with MPI_Errhandler_set ; the predefined error handler MPI_ERRORS_RETURN may be used to
cause error values to be returned (in C and Fortran; this error handler is less useful in
with the C++ MPI bindings. The predefined error handler MPI::ERRORS_THROW_EXCEPTIONS
should be used in C++ if the error value needs to be recovered). Note that MPI does not
guarantee that an MPI program can continue past an error.
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. The C++ bindings for
MPI do not return error values; instead, error values are communicated by throwing excep-
tions of type MPI::Exception (but not by default). Exceptions are only thrown if the
error value is not MPI::SUCCESS
Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return
upon an error, there will be no way to recover what the actual error value was.
- No error; MPI routine completed successfully.
- Invalid communicator. A common error is to use a null communicator in a call
(not even allowed in MPI_Comm_rank ).
- Invalid argument. Some argument is invalid and is not identified by a specific
error class. This is typically a NULL pointer or other such error.
- Other error; use MPI_Error_string to get more information about this error code.
- An internal error has been detected. This is fatal. Please send a bug report to
the LAM mailing list (see http://www.lam-mpi.org/contact.php ).
MPI_Put(3), MPI_Get(3), MPI_Accumulate(3), MPI_Win_start(3), MPI_Win_complete(3),
MPI_Win_fence(3), MPI_Win_free(3), MPI_Win_get_group(3), MPI_Win_get_group(3),
For more information, please see the official MPI Forum web site, which contains the text
of both the MPI-1 and MPI-2 standards. These documents contain detailed information about
each MPI function (most of which is not duplicated in these man pages).
LAM/MPI 6.5.8 11/10/2002 MPI_Win_create(3)