esp-idf/components/esp_event/include/esp_event_base.h

// Copyright 2018 Espressif Systems (Shanghai) PTE 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.

#ifndef ESP_EVENT_BASE_H_
#define ESP_EVENT_BASE_H_

#ifdef __cplusplus
extern "C" {
#endif

// Defines for declaring and defining event base
#define ESP_EVENT_DECLARE_BASE(id) extern esp_event_base_t id
#define ESP_EVENT_DEFINE_BASE(id) esp_event_base_t id = #id

// Event loop library types
typedef const char*  esp_event_base_t; /**< unique pointer to a subsystem that exposes events */
typedef void*        esp_event_loop_handle_t; /**< a number that identifies an event with respect to a base */
typedef void         (*esp_event_handler_t)(void* event_handler_arg, 
                                        esp_event_base_t event_base, 
                                        int32_t event_id, 
                                        void* event_data); /**< function called when an event is posted to the queue */


// Defines for registering/unregistering event handlers
#define ESP_EVENT_ANY_BASE     NULL             /**< register handler for any event base */
#define ESP_EVENT_ANY_ID       -1               /**< register handler for any event id */

#ifdef __cplusplus
}
#endif

#endif // #ifndef ESP_EVENT_BASE_H_