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)

INPUT PARAMETERS

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)

MORE INFORMATION

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