esp-idf/components/vfs/include/esp_vfs_eventfd.h

72 wiersze
2.0 KiB
C

// Copyright 2021 Espressif Systems (Shanghai) CO LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License
#pragma once
#include <stddef.h>
#include <sys/types.h>
#include "esp_err.h"
#define EFD_SUPPORT_ISR (1 << 4)
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Eventfd vfs initialization settings
*/
typedef struct {
size_t max_fds; /*!< The maxinum number of eventfds supported */
} esp_vfs_eventfd_config_t;
#define ESP_VFS_EVENTD_CONFIG_DEFAULT() (esp_vfs_eventfd_config_t) { \
.max_fds = 5, \
};
/**
* @brief Registers the event vfs.
*
* @return ESP_OK if successful, ESP_ERR_NO_MEM if too many VFSes are
* registered.
*/
esp_err_t esp_vfs_eventfd_register(const esp_vfs_eventfd_config_t *config);
/**
* @brief Unregisters the event vfs.
*
* @return ESP_OK if successful, ESP_ERR_INVALID_STATE if VFS for given prefix
* hasn't been registered
*/
esp_err_t esp_vfs_eventfd_unregister(void);
/*
* @brief Creates an event file descirptor.
*
* The behavior of read, write and select is the same as man(2) eventfd with
* EFD_SEMAPHORE **NOT** specified. A new flag EFD_SUPPORT_ISR has been added.
* This flag is required to write to event fds in interrupt handlers. Accessing
* the control blocks of event fds with EFD_SUPPORT_ISR will cause interrupts to
* be temporarily blocked (e.g. during read, write and beginning and ending of
* the * select).
*
* @return The file descriptor if successful, -1 if error happens.
*/
int eventfd(unsigned int initval, int flags);
#ifdef __cplusplus
}
#endif