76 lines
2.7 KiB
C
76 lines
2.7 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#pragma once
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/**
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* @file sys/eventfd.h
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* @brief Event notification file descriptors.
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*/
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#include <sys/cdefs.h>
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#include <fcntl.h>
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__BEGIN_DECLS
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/** The eventfd() flag to provide semaphore-like semantics for reads. */
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#define EFD_SEMAPHORE (1 << 0)
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/** The eventfd() flag for a close-on-exec file descriptor. */
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#define EFD_CLOEXEC O_CLOEXEC
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/** The eventfd() flag for a non-blocking file descriptor. */
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#define EFD_NONBLOCK O_NONBLOCK
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/**
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* [eventfd(2)](http://man7.org/linux/man-pages/man2/eventfd.2.html) creates a file descriptor
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* for event notification.
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*
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* Returns a new file descriptor on success, and returns -1 and sets `errno` on failure.
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*/
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int eventfd(unsigned int __initial_value, int __flags);
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/** The type used by eventfd_read() and eventfd_write(). */
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typedef uint64_t eventfd_t;
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/**
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* [eventfd_read(3)](http://man7.org/linux/man-pages/man2/eventfd.2.html) is a convenience
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* wrapper to read an `eventfd_t` from an eventfd file descriptor.
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*
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* Returns 0 on success, or returns -1 otherwise.
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*/
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int eventfd_read(int __fd, eventfd_t* __value);
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/**
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* [eventfd_write(3)](http://man7.org/linux/man-pages/man2/eventfd.2.html) is a convenience
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* wrapper to write an `eventfd_t` to an eventfd file descriptor.
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*
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* Returns 0 on success, or returns -1 otherwise.
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*/
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int eventfd_write(int __fd, eventfd_t __value);
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__END_DECLS
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