NAME¶
MPI_Win_start - Starts an RMA access epoch
SYNOPSIS¶
#include <mpi.h>
int MPI_Win_start(MPI_Group group, int assertion, MPI_Win win)
- group
- - group of origin processes (handle)
- assertion
- - program assertion (integer)
- win
- - window object (handle)
NOTES¶
Starts an RMA access epoch for win. RMA calls issued on win during this epoch
must access only windows at processes in group. Each process in group must
issue a matching call to MPI_WIN_POST. RMA accesses to each target window will
be delayed, if necessary, until the target process executed the matching call
to MPI_WIN_POST. MPI_WIN_START is allowed to block until the corresponding
MPI_WIN_POST calls are executed, but is not required to.
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.
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.
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 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 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_WIN
- - Invalid window. A common error is to use a null window in a call.
- MPI_ERR_GROUP
- - Null group passed to function.
- MPI_ERR_OTHER
- - Other error; use MPI_Error_string to get more information about
this error code.
- MPI_ERR_EPOCH
- - This error indicates than an operation has been attempted on a
"closed" window. Certain one-sided operations can only be
performed on windows whose epoch has been started with MPI_Win_start.
SEE ALSO¶
MPI_Put(3),
MPI_Get(3),
MPI_Win_create(3),
MPI_Accumulate(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 information about each MPI function (most of which is not duplicated
in these man pages).
http://www.mpi-forum.org/
LOCATION¶
wstart.c