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/*
ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS 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 3 of the License, or
(at your option) any later version.
ChibiOS 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, see <http://www.gnu.org/licenses/>.
*/
/**
* @file rt/include/chmsg.h
* @brief Messages macros and structures.
*
* @addtogroup messages
* @{
*/
#ifndef CHMSG_H
#define CHMSG_H
#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
/*===========================================================================*/
/* Module constants. */
/*===========================================================================*/
/*===========================================================================*/
/* Module pre-compile time settings. */
/*===========================================================================*/
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
/*===========================================================================*/
/* Module data structures and types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module macros. */
/*===========================================================================*/
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
#ifdef __cplusplus
extern "C" {
#endif
msg_t chMsgSend(thread_t *tp, msg_t msg);
thread_t *chMsgWaitS(void);
thread_t *chMsgWaitTimeoutS(sysinterval_t timeout);
thread_t *chMsgPollS(void);
void chMsgRelease(thread_t *tp, msg_t msg);
#ifdef __cplusplus
}
#endif
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
/**
* @brief Suspends the thread and waits for an incoming message.
* @post After receiving a message the function @p chMsgGet() must be
* called in order to retrieve the message and then @p chMsgRelease()
* must be invoked in order to acknowledge the reception and send
* the answer.
* @note If the message is a pointer then you can assume that the data
* pointed by the message is stable until you invoke @p chMsgRelease()
* because the sending thread is suspended until then.
* @note The reference counter of the sender thread is not increased, the
* returned pointer is a temporary reference.
*
* @return A pointer to the thread carrying the message.
*
* @api
*/
static inline thread_t *chMsgWait(void) {
thread_t *tp;
chSysLock();
tp = chMsgWaitS();
chSysUnlock();
return tp;
}
/**
* @brief Suspends the thread and waits for an incoming message or a
* timeout to occur.
* @post After receiving a message the function @p chMsgGet() must be
* called in order to retrieve the message and then @p chMsgRelease()
* must be invoked in order to acknowledge the reception and send
* the answer.
* @note If the message is a pointer then you can assume that the data
* pointed by the message is stable until you invoke @p chMsgRelease()
* because the sending thread is suspended until then.
* @note The reference counter of the sender thread is not increased, the
* returned pointer is a temporary reference.
*
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return A pointer to the thread carrying the message.
* @retval NULL if a timeout occurred.
*
* @api
*/
static inline thread_t *chMsgWaitTimeout(sysinterval_t timeout) {
thread_t *tp;
chSysLock();
tp = chMsgWaitTimeoutS(timeout);
chSysUnlock();
return tp;
}
/**
* @brief Poll to check for an incoming message.
* @post If a message is available the function @p chMsgGet() must be
* called in order to retrieve the message and then @p chMsgRelease()
* must be invoked in order to acknowledge the reception and send
* the answer.
* @note If the message is a pointer then you can assume that the data
* pointed by the message is stable until you invoke @p chMsgRelease()
* because the sending thread is suspended until then.
* @note The reference counter of the sender thread is not increased, the
* returned pointer is a temporary reference.
*
* @return A pointer to the thread carrying the message.
* @retval NULL if no incoming message waiting.
*
* @api
*/
static inline thread_t *chMsgPoll(void) {
thread_t *tp;
chSysLock();
tp = chMsgPollS();
chSysUnlock();
return tp;
}
/**
* @brief Evaluates to @p true if the thread has pending messages.
*
* @param[in] tp pointer to the thread
* @return The pending messages status.
*
* @iclass
*/
static inline bool chMsgIsPendingI(thread_t *tp) {
chDbgCheckClassI();
return (bool)(tp->msgqueue.next != (thread_t *)&tp->msgqueue);
}
/**
* @brief Returns the message carried by the specified thread.
* @pre This function must be invoked immediately after exiting a call
* to @p chMsgWait().
*
* @param[in] tp pointer to the thread
* @return The message carried by the sender.
*
* @api
*/
static inline msg_t chMsgGet(thread_t *tp) {
chDbgAssert(tp->state == CH_STATE_SNDMSG, "invalid state");
return tp->u.sentmsg;
}
/**
* @brief Releases the thread waiting on top of the messages queue.
* @pre Invoke this function only after a message has been received
* using @p chMsgWait().
*
* @param[in] tp pointer to the thread
* @param[in] msg message to be returned to the sender
*
* @sclass
*/
static inline void chMsgReleaseS(thread_t *tp, msg_t msg) {
chDbgCheckClassS();
chSchWakeupS(tp, msg);
}
#endif /* CH_CFG_USE_MESSAGES == TRUE */
#endif /* CHMSG_H */
/** @} */
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