50 lines
1.7 KiB
Plaintext
50 lines
1.7 KiB
Plaintext
[/
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/ Copyright (c) 2003-2019 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:SyncRandomAccessReadDevice Buffer-oriented synchronous random-access
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read device requirements]
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In the table below, `a` denotes a synchronous random-access read device object,
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`o` denotes an offset of type `boost::uint64_t`, `mb` denotes an object
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satisfying [link boost_asio.reference.MutableBufferSequence mutable buffer sequence]
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requirements, and `ec` denotes an object of type `error_code`.
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[table Buffer-oriented synchronous random-access read device requirements
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[[operation] [type] [semantics, pre/post-conditions]]
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[
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[`a.read_some_at(o, mb);`]
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[`size_t`]
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[Equivalent to:
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``
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error_code ec;
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size_t s = a.read_some_at(o, mb, ec);
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if (ec) throw system_error(ec);
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return s;
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``]
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]
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[
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[`a.read_some_at(o, mb, ec);`]
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[`size_t`]
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[
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Reads one or more bytes of data from the device `a` at offset `o`.\n
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\n
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The mutable buffer sequence `mb` specifies memory where the data should
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be placed. The `read_some_at` operation shall always fill a buffer in the
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sequence completely before proceeding to the next.\n
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\n
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If successful, returns the number of bytes read and sets `ec` such that
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`!ec` is true. If an error occurred, returns `0` and sets `ec` such that
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`!!ec` is true.\n
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\n
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If the total size of all buffers in the sequence `mb` is `0`, the
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function shall return `0` immediately.
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]
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]
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]
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[endsect]
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