1 /* 2 * Copyright (c) 2020 Tobias Svehagen 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 7 #ifndef ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_ 8 #define ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_ 9 10 #include <stdint.h> 11 12 #include <zephyr/kernel.h> 13 #include <zephyr/posix/fcntl.h> 14 15 #ifdef __cplusplus 16 extern "C" { 17 #endif 18 19 #define EFD_IN_USE 0x1 __DEPRECATED_MACRO 20 #define EFD_SEMAPHORE 0x2 21 #define EFD_NONBLOCK O_NONBLOCK 22 #define EFD_FLAGS_SET (EFD_SEMAPHORE | EFD_NONBLOCK) __DEPRECATED_MACRO 23 24 typedef uint64_t eventfd_t; 25 26 /** 27 * @brief Create a file descriptor for event notification 28 * 29 * The returned file descriptor can be used with POSIX read/write calls or 30 * with the eventfd_read/eventfd_write functions. 31 * 32 * It also supports polling and by including an eventfd in a call to poll, 33 * it is possible to signal and wake the polling thread by simply writing to 34 * the eventfd. 35 * 36 * When using read() and write() on an eventfd, the size must always be at 37 * least 8 bytes or the operation will fail with EINVAL. 38 * 39 * @return New eventfd file descriptor on success, -1 on error 40 */ 41 int eventfd(unsigned int initval, int flags); 42 43 /** 44 * @brief Read from an eventfd 45 * 46 * If call is successful, the value parameter will have the value 1 47 * 48 * @param fd File descriptor 49 * @param value Pointer for storing the read value 50 * 51 * @return 0 on success, -1 on error 52 */ 53 int eventfd_read(int fd, eventfd_t *value); 54 55 /** 56 * @brief Write to an eventfd 57 * 58 * @param fd File descriptor 59 * @param value Value to write 60 * 61 * @return 0 on success, -1 on error 62 */ 63 int eventfd_write(int fd, eventfd_t value); 64 65 #ifdef __cplusplus 66 } 67 #endif 68 69 #endif /* ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_ */ 70
