components/vfs/include/esp_vfs_eventfd.h (ESP-IDF)

/* * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #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 maximum 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 descriptor. * * 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