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MPI_Win_allocate_shared(3)             MPI            MPI_Win_allocate_shared(3)




NAME

       MPI_Win_allocate_shared -  Create an MPI Window object for one-sided
       communication and shared memory access, and allocate memory at each
       process


SYNOPSIS

       int MPI_Win_allocate_shared(MPI_Aint size, int disp_unit, MPI_Info info,
       MPI_Comm comm, void *baseptr, MPI_Win *win)

       int MPI_Win_allocate_shared_c(MPI_Aint size, MPI_Aint disp_unit, MPI_Info info,
       MPI_Comm comm, void *baseptr, MPI_Win *win)




INPUT PARAMETERS

       size   - size of local window in bytes (non-negative integer)
       disp_unit
              - local unit size for displacements, in bytes (positive integer)
       info   - info argument (handle)
       comm   - intra-communicator (handle)



OUTPUT PARAMETERS

       baseptr
              - address of local allocated window segment (choice)
       win    - window object returned by the call (handle)

              This is a collective call executed by all processes in the group
              of comm. On each process i, it allocates memory of at least size
              bytes that is shared among all processes in comm, and returns a
              pointer to the locally allocated segment in baseptr that can be
              used for load/store accesses on the calling process. The locally
              allocated memory can be the target of load/store accesses by
              remote processes; the base pointers for other processes can be
              queried using the function MPI_Win_shared_query .


              The call also returns a window object that can be used by all
              processes in comm to perform RMA operations. The size argument may
              be different at each process and size = 0 is valid. It is the
              user's responsibility to ensure that the communicator comm
              represents a group of processes that can create a shared memory
              segment that can be accessed by all processes in the group. The
              allocated memory is contiguous across process ranks unless the
              info key alloc_shared_noncontig is specified. Contiguous across
              process ranks means that the first address in the memory segment
              of process i is consecutive with the last address in the memory
              segment of process i - 1. This may enable the user to calculate
              remote address offsets with local information only.



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
       guarantee 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_COMM
              - Invalid communicator.  A common error is to use a null
              communicator in a call (not even allowed in MPI_Comm_rank ).
       MPI_ERR_DISP
              -
       MPI_ERR_INFO
              - Invalid Info
       MPI_ERR_SIZE
              -
       MPI_ERR_OTHER
              - Other error; use MPI_Error_string to get more information about
              this error code.



SEE ALSO

       MPI_Win_allocate MPI_Win_create MPI_Win_create_dynamic MPI_Win_free
       MPI_Win_shared_query



                                    1/27/2023         MPI_Win_allocate_shared(3)

mpi 4.1 - Generated Sat Jan 28 18:12:44 CST 2023
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