58 lines
2.3 KiB
Plaintext
58 lines
2.3 KiB
Plaintext
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/ Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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/
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/ Distributed under the Boost Software License, Version 1.0. (See accompanying
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/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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/]
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[section:AsyncRandomAccessWriteDevice Buffer-oriented asynchronous
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random-access write device requirements]
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In the table below, `a` denotes an asynchronous write stream object, `o`
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denotes an offset of type `boost::uint64_t`, `cb` denotes an object satisfying
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[link boost_asio.reference.ConstBufferSequence constant buffer sequence]
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requirements, and `h` denotes an object satisfying [link
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boost_asio.reference.WriteHandler write handler] requirements.
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[table Buffer-oriented asynchronous random-access write device requirements
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[[operation] [type] [semantics, pre/post-conditions]]
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[
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[`a.get_executor()`]
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[A type satisfying the [link boost_asio.reference.Executor1 Executor requirements].]
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[Returns the associated I/O executor.]
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]
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[
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[`a.async_write_some_at(o, cb, h);`]
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[`void`]
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[
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Initiates an asynchronous operation to write one or more bytes of data to
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the device `a` at offset `o`. The operation is performed via the
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`io_service` object `a.get_io_service()` and behaves according to [link
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boost_asio.reference.asynchronous_operations asynchronous operation]
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requirements.[br]
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[br]
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The constant buffer sequence `cb` specifies memory where the data to be
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written is located. The `async_write_some_at` operation shall always
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write a buffer in the sequence completely before proceeding to the
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next.[br]
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[br]
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The implementation shall maintain one or more copies of `cb` until such
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time as the write operation no longer requires access to the memory
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specified by the buffers in the sequence. The program must ensure the
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memory is valid until:[br]
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[br]
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[mdash] the last copy of `cb` is destroyed, or[br]
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[br]
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[mdash] the handler for the asynchronous write operation is invoked,[br]
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[br]
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whichever comes first.[br]
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[br]
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If the total size of all buffers in the sequence `cb` is `0`, the
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asynchronous write operation shall complete immediately and pass `0` as
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the argument to the handler that specifies the number of bytes written.
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]
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]
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]
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[endsect]
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