163 lines
3.5 KiB
Groff
163 lines
3.5 KiB
Groff
.TH MPI_Win_lock 3 "2/3/2025" " " "MPI"
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.SH NAME
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MPI_Win_lock \- Begin an RMA access epoch at the target process
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.SH SYNOPSIS
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.nf
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.fi
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.nf
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int MPI_Win_lock(int lock_type, int rank, int assert, MPI_Win win)
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.fi
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.SH INPUT PARAMETERS
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.PD 0
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.TP
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.B lock_type
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- either MPI_LOCK_EXCLUSIVE or MPI_LOCK_SHARED (state)
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.PD 1
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.PD 0
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.TP
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.B rank
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- rank of locked window (non-negative integer)
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.PD 1
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.PD 0
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.TP
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.B assert
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- program assertion (integer)
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.PD 1
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.PD 0
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.TP
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.B win
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- window object (handle)
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.PD 1
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.SH NOTES
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The name of this routine is misleading. In particular, this
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routine need not block, except when the target process is the calling
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process.
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Implementations may restrict the use of RMA communication that is
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synchronized
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by lock calls to windows in memory allocated by
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.I MPI_Alloc_mem
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\&.
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Locks can
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be used portably only in such memory.
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The
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.I assert
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argument is used to indicate special conditions for the
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fence that an implementation may use to optimize the
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.I MPI_Win_lock
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operation. The value zero is always correct. Other assertion values
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may be or'ed together. Assertions that are valid for
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.I MPI_Win_lock
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are:
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.PD 0
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.TP
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.B MPI_MODE_NOCHECK
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- no other process holds, or will attempt to acquire a
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conflicting lock, while the caller holds the window lock. This is useful
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when mutual exclusion is achieved by other means, but the coherence
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operations that may be attached to the lock and unlock calls are still
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required.
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.PD 1
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.SH THREAD AND INTERRUPT SAFETY
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This routine is thread-safe. This means that this routine may be
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safely used by multiple threads without the need for any user-provided
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thread locks. However, the routine is not interrupt safe. Typically,
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this is due to the use of memory allocation routines such as
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.I malloc
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or other non-MPICH runtime routines that are themselves not interrupt-safe.
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.SH NOTES FOR FORTRAN
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All MPI routines in Fortran (except for
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.I MPI_WTIME
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and
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.I MPI_WTICK
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) have
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an additional argument
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.I ierr
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at the end of the argument list.
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.I ierr
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is an integer and has the same meaning as the return value of the routine
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in C. In Fortran, MPI routines are subroutines, and are invoked with the
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.I call
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statement.
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All MPI objects (e.g.,
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.I MPI_Datatype
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,
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.I MPI_Comm
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) are of type
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.I INTEGER
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in Fortran.
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.SH ERRORS
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All MPI routines (except
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.I MPI_Wtime
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and
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.I MPI_Wtick
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) return an error value;
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C routines as the value of the function and Fortran routines in the last
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argument. Before the value is returned, the current MPI error handler is
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called. By default, this error handler aborts the MPI job. The error handler
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may be changed with
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.I MPI_Comm_set_errhandler
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(for communicators),
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.I MPI_File_set_errhandler
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(for files), and
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.I MPI_Win_set_errhandler
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(for
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RMA windows). The MPI-1 routine
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.I MPI_Errhandler_set
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may be used but
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its use is deprecated. The predefined error handler
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.I MPI_ERRORS_RETURN
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may be used to cause error values to be returned.
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Note that MPI does
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.B not
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guarantee that an MPI program can continue past
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an error; however, MPI implementations will attempt to continue whenever
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possible.
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.PD 0
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.TP
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.B MPI_SUCCESS
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- No error; MPI routine completed successfully.
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_RANK
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- Invalid source or destination rank. Ranks must be between
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zero and the size of the communicator minus one; ranks in a receive
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(
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.I MPI_Recv
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,
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.I MPI_Irecv
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,
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.I MPI_Sendrecv
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, etc.) may also be
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.I MPI_ANY_SOURCE
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\&.
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_WIN
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- Invalid MPI window object
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_OTHER
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- Other error; use
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.I MPI_Error_string
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to get more information
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about this error code.
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.PD 1
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