/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/uds-releases/jasper/src/uds/threadOnce.h#1 $

 */

#ifndef THREAD_ONCE_H

#define THREAD_ONCE_H

#include "atomicDefs.h"

#define ONCE_STATE_INITIALIZER ATOMIC_INIT(0)

typedef atomic_t OnceState;

/**

 * Thread safe once only initialization.

 *

 * @param onceState    pointer to object to record that initialization

 *                     has been performed

 * @param initFunction called if onceState does not indicate

 *                     initialization has been performed

 *

 * @return             UDS_SUCCESS or error code

 *

 * @note Generally the following declaration of onceState is performed in

 *       at file scope:

 *

 *       static OnceState onceState = ONCE_STATE_INITIALIZER;

 **/

int performOnce(OnceState *onceState, void (*initFunction) (void));

#endif /* THREAD_ONCE_H */