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https://github.com/espressif/esp-idf.git
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f6fd2eb164
eventfd imitates the behavior of POSIX api `man(2) eventfd`. This api can be used to pass events to a select based message loop.
62 lines
1.8 KiB
C
62 lines
1.8 KiB
C
// Copyright 2021 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License
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#pragma once
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#include <stddef.h>
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#include <sys/types.h>
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#include "esp_err.h"
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#define EFD_SUPPORT_ISR (1 << 4)
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#define EVENT_VFS_PREFIX "/dev/event"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Registers the event vfs.
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*
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* @return ESP_OK if successful, ESP_ERR_NO_MEM if too many VFSes are
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* registered.
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*/
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esp_err_t esp_vfs_eventfd_register(void);
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/**
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* @brief Unregisters the event vfs.
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*
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* @return ESP_OK if successful, ESP_ERR_INVALID_STATE if VFS for given prefix
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* hasn't been registered
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*/
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esp_err_t esp_vfs_eventfd_unregister(void);
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/*
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* @brief Creates an event file descirptor.
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*
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* The behavior of read, write and select is the same as man(2) eventfd with
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* EFD_SEMAPHORE **NOT** specified. A new flag EFD_SUPPORT_ISR has been added.
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* This flag is required to write to event fds in interrupt handlers. Accessing
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* the control blocks of event fds with EFD_SUPPORT_ISR will cause interrupts to
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* be temporarily blocked (e.g. during read, write and beginning and ending of
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* the * select).
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*
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* @return The file descriptor if successful, -1 if error happens.
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*/
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int eventfd(unsigned int initval, int flags);
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#ifdef __cplusplus
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}
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#endif
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