NAME¶
MPI_Win_shared_query - Query the size and base pointer for a patch of a shared
memory window.
SYNOPSIS¶
int MPI_Win_shared_query(MPI_Win win, int rank, MPI_Aint *size, int *disp_unit, void *baseptr)
This function queries the process-local address for remote memory segments
created with
MPI_Win_allocate_shared . This function can return
different process-local addresses for the same physical memory on different
processes.
The returned memory can be used for load/store accesses subject to the
constraints defined in MPI 3.0, Section 11.7. This function can only be called
with windows of type
MPI_Win_flavor_shared . If the passed window is
not of flavor
MPI_Win_flavor_shared , the error
MPI_ERR_RMA_FLAVOR is raised. When rank is
MPI_PROC_NULL , the
pointer, disp_unit, and size returned are the pointer, disp_unit, and size of
the memory segment belonging the lowest rank that specified size > 0. If
all processes in the group attached to the window specified size = 0, then the
call returns size = 0 and a baseptr as if
MPI_Alloc_mem was called with
size = 0.
- win
- - window object used for communication (handle)
- rank
- - target rank
OUTPUT PARAMETERS¶
- size
- - size of the segment at the given rank
- disp_unit
- - local unit size for displacements, in bytes (positive integer)
- baseptr
- - base pointer in the calling process' address space of the shared segment
belonging to the target rank.
THREAD AND INTERRUPT SAFETY¶
This routine is thread-safe. This means that this routine may be safely used by
multiple threads without the need for any user-provided thread locks. However,
the routine is not interrupt safe. Typically, this is due to the use of memory
allocation routines such as
malloc or other non-MPICH runtime routines
that are themselves not interrupt-safe.
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 communicators),
MPI_File_set_errhandler (for files), and
MPI_Win_set_errhandler
(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 whenever possible.
- MPI_SUCCESS
- - No error; MPI routine completed successfully.
- MPI_ERR_ARG
- - Invalid argument. Some argument is invalid and is not identified by a
specific error class (e.g., MPI_ERR_RANK ).
- MPI_ERR_RANK
- - Invalid source or destination rank. Ranks must be between zero and the
size of the communicator minus one; ranks in a receive ( MPI_Recv ,
MPI_Irecv , MPI_Sendrecv , etc.) may also be
MPI_ANY_SOURCE .
- MPI_ERR_WIN
- - Invalid MPI window object
SEE ALSO¶
MPI_Win_allocate_shared
LOCATION¶
/tmp/gyCYfBi4J6/mpich-3.1/src/mpi/rma/win_shared_query.c