83 lines
2.3 KiB
C++
83 lines
2.3 KiB
C++
/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* https://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2023 Andrey Semashev
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*/
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/*!
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* \file scope/fd_deleter.hpp
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*
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* This header contains definition of a deleter function object for
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* POSIX-like file descriptors for use with \c unique_resource.
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*/
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#ifndef BOOST_SCOPE_FD_DELETER_HPP_INCLUDED_
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#define BOOST_SCOPE_FD_DELETER_HPP_INCLUDED_
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#include <boost/scope/detail/config.hpp>
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#if !defined(BOOST_WINDOWS)
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#include <unistd.h>
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#if defined(hpux) || defined(_hpux) || defined(__hpux)
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#include <cerrno>
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#endif
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#else // !defined(BOOST_WINDOWS)
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#include <io.h>
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#endif // !defined(BOOST_WINDOWS)
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#include <boost/scope/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace scope {
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//! POSIX-like file descriptor deleter
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struct fd_deleter
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{
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using result_type = void;
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//! Closes the file descriptor
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result_type operator() (int fd) const noexcept
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{
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#if !defined(BOOST_WINDOWS)
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#if defined(hpux) || defined(_hpux) || defined(__hpux)
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// Some systems don't close the file descriptor in case if the thread is interrupted by a signal and close(2) returns EINTR.
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// Other (most) systems do close the file descriptor even when when close(2) returns EINTR, and attempting to close it
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// again could close a different file descriptor that was opened by a different thread.
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//
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// Future POSIX standards will likely fix this by introducing posix_close (see https://www.austingroupbugs.net/view.php?id=529)
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// and prohibiting returning EINTR from close(2), but we still have to support older systems where this new behavior is not available and close(2)
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// behaves differently between systems.
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int res;
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while (true)
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{
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res = ::close(fd);
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if (BOOST_UNLIKELY(res < 0))
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{
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int err = errno;
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if (err == EINTR)
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continue;
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}
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break;
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}
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#else
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::close(fd);
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#endif
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#else // !defined(BOOST_WINDOWS)
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::_close(fd);
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#endif // !defined(BOOST_WINDOWS)
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}
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};
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} // namespace scope
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} // namespace boost
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#include <boost/scope/detail/footer.hpp>
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#endif // BOOST_SCOPE_FD_DELETER_HPP_INCLUDED_
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