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- [/
- / Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
- /
- / Distributed under the Boost Software License, Version 1.0. (See accompanying
- / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- /]
- [section:SyncRandomAccessReadDevice Buffer-oriented synchronous random-access
- read device requirements]
- In the table below, `a` denotes a synchronous random-access read device object,
- `o` denotes an offset of type `boost::uint64_t`, `mb` denotes an object
- satisfying [link boost_asio.reference.MutableBufferSequence mutable buffer sequence]
- requirements, and `ec` denotes an object of type `error_code`.
- [table Buffer-oriented synchronous random-access read device requirements
- [[operation] [type] [semantics, pre/post-conditions]]
- [
- [`a.read_some_at(o, mb);`]
- [`size_t`]
- [Equivalent to:
- ``
- error_code ec;
- size_t s = a.read_some_at(o, mb, ec);
- if (ec) throw system_error(ec);
- return s;
- ``]
- ]
- [
- [`a.read_some_at(o, mb, ec);`]
- [`size_t`]
- [
- Reads one or more bytes of data from the device `a` at offset `o`.\n
- \n
- The mutable buffer sequence `mb` specifies memory where the data should
- be placed. The `read_some_at` operation shall always fill a buffer in the
- sequence completely before proceeding to the next.\n
- \n
- If successful, returns the number of bytes read and sets `ec` such that
- `!ec` is true. If an error occurred, returns `0` and sets `ec` such that
- `!!ec` is true.\n
- \n
- If the total size of all buffers in the sequence `mb` is `0`, the
- function shall return `0` immediately.
- ]
- ]
- ]
- [endsect]
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