MPI_Win_create - Specifies an window accessible by remote
processes
SYNOPSIS
#include <mpi.h>
int
MPI_Win_create(void *base, MPI_Aint size, int disp_unit,
MPI_Info info, MPI_Comm comm, MPI_Win *newwin)
INPUT PARAMETERS
base - initial address of window (choice)
size - size of window in bytes (nonnegative integer)
disp_unit
- local unit size for displacements, in bytes (pos
itive integer)
info - info argument (handle)
comm - communicator (handle)
newwin - window object returned by the call (handle)
NOTES
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 provides 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 windows, 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 prob
lem. The same area in memory may appear in multiple win
dows, each associated with a different window object. How
ever, 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 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 For
tran, 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.
The IMPI standard only supports MPI-1 functions. Hence,
this function is currently not designed to operate within
an IMPI job.
ERRORS
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 val
ues to be returned (in C and Fortran; this error handler
is less useful in with the C++ MPI bindings. The prede
fined 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++ bind
ings for MPI do not return error values; instead, error
values are communicated by throwing exceptions 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.
MPI_SUCCESS
- No error; MPI routine completed successfully.
MPI_ERR_COMM
- Invalid communicator. A common error is to use a
null communicator in a call (not even allowed in
MPI_Comm_rank ).
MPI_ERR_ARG
- 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.
MPI_ERR_OTHER
- Other error; use MPI_Error_string to get more
information about this error code.
MPI_ERR_INTERN
- 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 ).
SEE ALSO
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), MPI_Win_wait(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 infor
mation about each MPI function (most of which is not
duplicated in these man pages).
http://www.mpi-forum.org/
LOCATION
wcreate.c
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