uC/OS-II 函数之邮箱管理相关函数
上文主要介绍了消息队列相关的函数，本文介绍邮箱管理相关的函数：OSMboxCreate()建立一个邮箱,OSMboxDel()删除一个邮箱,OSMboxPend()等待邮箱中的消息,OSMboxPost()向邮箱发送一则消息，OSMboxQuery()查询一个邮箱的状态.
邮箱管里介绍
邮箱是µC/OS-II中另一种通讯机制，它可以使一个任务或者中断服务子程序向另一个任务发送一个指针型的变量。该指针指向一个包含了特定“消息”的数据结构。为了在µC/OS-II中使用邮箱，必须将OS_CFG.H中的OS_MBOX_EN常数置为1。
使用邮箱之前，必须先建立该邮箱。该操作可以通过调用OSMboxCreate()函数来完成（见下节），并且要指定指针的初始值。一般情况下，这个初始值是NULL，但也可以初始化一个邮箱，使其在最开始就包含一条消息。如果使用邮箱的目的是用来通知一个事件的发生（发送一条消息），那么就要初始化该邮箱为NULL，因为在开始时，事件还没有发生。如果用户用邮箱来共享某些资源，那么就要初始化该邮箱为一个非NULL的指针。在这种情况下，邮箱被当成一个二值信号量使用。
µC/OS-II提供了6种对邮箱的操作：OSMboxCreate()，OSMboxDel()，OSMboxPend()，OSMboxPost()，OSMboxAccept()和OSMboxQuery()函数。图 F10.6描述了任务、中断服务子程序和邮箱之间的关系，这里用符号“I”表示邮箱。邮箱包含的内容是一个指向一条消息的指针。一个邮箱只能包含一个这样的指针（邮箱为满时），或者一个指向NULL的指针（邮箱为空时）。从图 F10.6可以看出，任务或者中断服务子程序可以调用函数OSMboxPost()，但是只有任务可以调用函数OSMboxPend()和OSMboxQuery()。
OSMboxCreate()建立一个邮箱
1主要作用：基本上和函数OSSemCreate()相似。建立一个邮箱变量；
2函数原型：OS_EVENT *OSMboxCreate (void *msg)
3参数说明：msg 是一个要在任务间传递的变量指针
4返回值说明：OSMboxCreate()函数的返回值是一个指向事件控制块的指针[L10.14(3)]。这个指针在调用函数OSMboxPend()，OSMboxPost()，OSMboxAccept()和OSMboxQuery()时使用。因此，该指针可以看作是对应邮箱的句柄。值得注意的是，如果系统中已经没有事件控制块可用，函数OSMboxCreate()将返回一个NULL指针。
5函数主体在os_mbox.c中
OSMboxDel()删除一个邮箱
1、主要作用：对一个不再使用的消息邮箱要及时删除以释放资源。
2、函数原型：OS_EVENT *OSMboxDel (OS_EVENT pevent, INT8U opt, INT8U err)
3、参数说明：pevent邮箱句柄
opt == OS_DEL_NO_PEND 如果没有等待任务时删除邮箱；
opt == OS_DEL_ALWAYS 无条件删除又向，所有等待该事件的任务急转到就绪状态；
err 是本函数执行状态的返回值，err 的值含义：
ØOS_NO_ERR ---- 函数成功，指定的邮箱被删除；
ØOS_INVALID_OPT ---- 删除方式数据错；
ØOS_ERR_EVENT_TYPE ---- 欲删除的事件类型不是邮箱；
ØOS_ERR_DEL_ISR ---- 不支持ISR中的消息邮箱删除操作；
ØOS_ERR_PEVENT_NULL ---- 指定的事件为空（不存在）；
ØOS_ERR_TASK_WAITING ---- 邮箱中还有等待任务；
4、返回值说明：删除的句柄
5函数主体在os_mbox.c中
OSMboxPend()等待邮箱中的消息
1、主要作用 ：所谓的 “请求消息邮箱” 就是等待一个消息传送到消息邮箱，或取得一个消息数据。
2、函数原型：void *OSMboxPend (OS_EVENT *pevent, INT16U timeout, INT8U err)
3、参数说明：pevent消息邮箱指针；timeout等待时限；err函数执行信息；
4、返回值说明：返回值为空时意味着未得到消息，此时uC/OS-II执行OS_Sched()；可能消息未准备好，或指示的事件出错、超时等，此时函数直接返回，用户应查阅 *err的状态。
当返回值 != Null 时，返回值就是一个预期消息的指针；
5函数主体在os_mbox.c中
OSMboxPost()向邮箱发送一则消息，
1、主要作用：可以调用系统函数OSMboxPost( )函数向消息邮箱发送消息；
2、函数原型：INT8U OSMboxPost (OS_EVENT *pevent, void *msg)
3、参数说明：形参 msg 是一个要在任务间传递的变量指针；形参 pevent 是消息邮箱指针；
4、返回值说明：
1、OS_NO_ERR ---- 消息发送成功；
2、 OS_MBOX_FULL ---- 不能向满邮箱再发送消息；
3、OS_ERR_EVENT_TYPE ---- 指定的事件不是消息邮箱类型；
4、OS_ERR_PEVENT_NULL ---- 不能向不存在的消息邮箱发送消息；
5、OS_ERR_POST_NULL_PTR ---- 消息缓冲区不能为空；
5函数主体在os_mbox.c中
向邮箱发送一则消息可以用下面函数，功能更强大，可发送广播消息
INT8U OSMboxPostOpt (OS_EVENT *pevent, void *msg, INT8U opt)
OSMboxQuery()查询一个邮箱的状态
1、主要作用：函数使应用程序可以随时查询一个邮箱的当前状态
2、函数原型：INT8U OSMboxQuery (OS_EVENT *pevent, OS_MBOX_DATA *pdata)
3、参数说明：一个是指向邮箱的指针pevent。该指针是在建立该邮箱时，由OSMboxCreate()函数返回的；另一个是指向用来保存有关邮箱的信息的OS_MBOX_DATA（见uCOS_II.H）数据结构的指针pdata。
４、返回值说明：OS_NO_ERR ：调用成功
OS_ERR_EVENT_TYPE ：pevent 不是指向消息邮箱的指针。
注意/警告:必须先建立消息邮箱，然后使用。
5函数主体在os_mbox.c中
附os_mbox.c代码：
/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
* MESSAGE MAILBOX MANAGEMENT
*
* (c) Copyright 1992-2013, Micrium, Weston, FL
* All Rights Reserved
*
* File : OS_MBOX.C
* By : Jean J. Labrosse
* Version : V2.92.08
*
* LICENSING TERMS:
* ---------------
* uC/OS-II is provided in source form for FREE evaluation, for educational use or for peaceful research.
* If you plan on using uC/OS-II in a commercial product you need to contact Micrium to properly license
* its use in your product. We provide ALL the source code for your convenience and to help you experience
* uC/OS-II. The fact that the source is provided does NOT mean that you can use it without paying a
* licensing fee.
*********************************************************************************************************
*/
#define MICRIUM_SOURCE
#ifndef OS_MASTER_FILE
#include <ucos_ii.h>
#endif
#if OS_MBOX_EN > 0u
/*
*********************************************************************************************************
* ACCEPT MESSAGE FROM MAILBOX
*
* Description: This function checks the mailbox to see if a message is available. Unlike OSMboxPend(),
* OSMboxAccept() does not suspend the calling task if a message is not available.
*
* Arguments : pevent is a pointer to the event control block
*
* Returns : != (void *)0 is the message in the mailbox if one is available. The mailbox is cleared
* so the next time OSMboxAccept() is called, the mailbox will be empty.
* == (void *)0 if the mailbox is empty or,
* if 'pevent' is a NULL pointer or,
* if you didn't pass the proper event pointer.
*********************************************************************************************************
*/
#if OS_MBOX_ACCEPT_EN > 0u
void *OSMboxAccept (OS_EVENT *pevent)
{
void *pmsg;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
return ((void *)0);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
return ((void *)0);
}
OS_ENTER_CRITICAL();
pmsg = pevent->OSEventPtr;
pevent->OSEventPtr = (void *)0; /* Clear the mailbox */
OS_EXIT_CRITICAL();
return (pmsg); /* Return the message received (or NULL) */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* CREATE A MESSAGE MAILBOX
*
* Description: This function creates a message mailbox if free event control blocks are available.
*
* Arguments : pmsg is a pointer to a message that you wish to deposit in the mailbox. If
* you set this value to the NULL pointer (i.e. (void *)0) then the mailbox
* will be considered empty.
*
* Returns : != (OS_EVENT *)0 is a pointer to the event control clock (OS_EVENT) associated with the
* created mailbox
* == (OS_EVENT *)0 if no event control blocks were available
*********************************************************************************************************
*/
OS_EVENT *OSMboxCreate (void *pmsg)
{
OS_EVENT *pevent;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#ifdef OS_SAFETY_CRITICAL_IEC61508
if (OSSafetyCriticalStartFlag == OS_TRUE) {
OS_SAFETY_CRITICAL_EXCEPTION();
return ((OS_EVENT *)0);
}
#endif
if (OSIntNesting > 0u) { /* See if called from ISR ... */
return ((OS_EVENT *)0); /* ... can't CREATE from an ISR */
}
OS_ENTER_CRITICAL();
pevent = OSEventFreeList; /* Get next free event control block */
if (OSEventFreeList != (OS_EVENT *)0) { /* See if pool of free ECB pool was empty */
OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
}
OS_EXIT_CRITICAL();
if (pevent != (OS_EVENT *)0) {
pevent->OSEventType = OS_EVENT_TYPE_MBOX;
pevent->OSEventCnt = 0u;
pevent->OSEventPtr = pmsg; /* Deposit message in event control block */
#if OS_EVENT_NAME_EN > 0u
pevent->OSEventName = (INT8U *)(void *)"?";
#endif
OS_EventWaitListInit(pevent);
}
return (pevent); /* Return pointer to event control block */
}
/*$PAGE*/
/*
*********************************************************************************************************
* DELETE A MAIBOX
*
* Description: This function deletes a mailbox and readies all tasks pending on the mailbox.
*
* Arguments : pevent is a pointer to the event control block associated with the desired
* mailbox.
*
* opt determines delete options as follows:
* opt == OS_DEL_NO_PEND Delete the mailbox ONLY if no task pending
* opt == OS_DEL_ALWAYS Deletes the mailbox even if tasks are waiting.
* In this case, all the tasks pending will be readied.
*
* perr is a pointer to an error code that can contain one of the following values:
* OS_ERR_NONE The call was successful and the mailbox was deleted
* OS_ERR_DEL_ISR If you attempted to delete the mailbox from an ISR
* OS_ERR_INVALID_OPT An invalid option was specified
* OS_ERR_TASK_WAITING One or more tasks were waiting on the mailbox
* OS_ERR_EVENT_TYPE If you didn't pass a pointer to a mailbox
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
*
* Returns : pevent upon error
* (OS_EVENT *)0 if the mailbox was successfully deleted.
*
* Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
* the mailbox MUST check the return code of OSMboxPend().
* 2) OSMboxAccept() callers will not know that the intended mailbox has been deleted!
* 3) This call can potentially disable interrupts for a long time. The interrupt disable
* time is directly proportional to the number of tasks waiting on the mailbox.
* 4) Because ALL tasks pending on the mailbox will be readied, you MUST be careful in
* applications where the mailbox is used for mutual exclusion because the resource(s)
* will no longer be guarded by the mailbox.
* 5) All tasks that were waiting for the mailbox will be readied and returned an
* OS_ERR_PEND_ABORT if OSMboxDel() was called with OS_DEL_ALWAYS
*********************************************************************************************************
*/
#if OS_MBOX_DEL_EN > 0u
OS_EVENT *OSMboxDel (OS_EVENT *pevent,
INT8U opt,
INT8U *perr)
{
BOOLEAN tasks_waiting;
OS_EVENT *pevent_return;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#ifdef OS_SAFETY_CRITICAL
if (perr == (INT8U *)0) {
OS_SAFETY_CRITICAL_EXCEPTION();
return ((OS_EVENT *)0);
}
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*perr = OS_ERR_PEVENT_NULL;
return (pevent);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
*perr = OS_ERR_EVENT_TYPE;
return (pevent);
}
if (OSIntNesting > 0u) { /* See if called from ISR ... */
*perr = OS_ERR_DEL_ISR; /* ... can't DELETE from an ISR */
return (pevent);
}
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0u) { /* See if any tasks waiting on mailbox */
tasks_waiting = OS_TRUE; /* Yes */
} else {
tasks_waiting = OS_FALSE; /* No */
}
switch (opt) {
case OS_DEL_NO_PEND: /* Delete mailbox only if no task waiting */
if (tasks_waiting == OS_FALSE) {
#if OS_EVENT_NAME_EN > 0u
pevent->OSEventName = (INT8U *)(void *)"?";
#endif
pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
pevent->OSEventCnt = 0u;
OSEventFreeList = pevent; /* Get next free event control block */
OS_EXIT_CRITICAL();
*perr = OS_ERR_NONE;
pevent_return = (OS_EVENT *)0; /* Mailbox has been deleted */
} else {
OS_EXIT_CRITICAL();
*perr = OS_ERR_TASK_WAITING;
pevent_return = pevent;
}
break;
case OS_DEL_ALWAYS: /* Always delete the mailbox */
while (pevent->OSEventGrp != 0u) { /* Ready ALL tasks waiting for mailbox */
(void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX, OS_STAT_PEND_ABORT);
}
#if OS_EVENT_NAME_EN > 0u
pevent->OSEventName = (INT8U *)(void *)"?";
#endif
pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
pevent->OSEventCnt = 0u;
OSEventFreeList = pevent; /* Get next free event control block */
OS_EXIT_CRITICAL();
if (tasks_waiting == OS_TRUE) { /* Reschedule only if task(s) were waiting */
OS_Sched(); /* Find highest priority task ready to run */
}
*perr = OS_ERR_NONE;
pevent_return = (OS_EVENT *)0; /* Mailbox has been deleted */
break;
default:
OS_EXIT_CRITICAL();
*perr = OS_ERR_INVALID_OPT;
pevent_return = pevent;
break;
}
return (pevent_return);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* PEND ON MAILBOX FOR A MESSAGE
*
* Description: This function waits for a message to be sent to a mailbox
*
* Arguments : pevent is a pointer to the event control block associated with the desired mailbox
*
* timeout is an optional timeout period (in clock ticks). If non-zero, your task will
* wait for a message to arrive at the mailbox up to the amount of time
* specified by this argument. If you specify 0, however, your task will wait
* forever at the specified mailbox or, until a message arrives.
*
* perr is a pointer to where an error message will be deposited. Possible error
* messages are:
*
* OS_ERR_NONE The call was successful and your task received a
* message.
* OS_ERR_TIMEOUT A message was not received within the specified 'timeout'.
* OS_ERR_PEND_ABORT The wait on the mailbox was aborted.
* OS_ERR_EVENT_TYPE Invalid event type
* OS_ERR_PEND_ISR If you called this function from an ISR and the result
* would lead to a suspension.
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer
* OS_ERR_PEND_LOCKED If you called this function when the scheduler is locked
*
* Returns : != (void *)0 is a pointer to the message received
* == (void *)0 if no message was received or,
* if 'pevent' is a NULL pointer or,
* if you didn't pass the proper pointer to the event control block.
*********************************************************************************************************
*/
/*$PAGE*/
void *OSMboxPend (OS_EVENT *pevent,
INT32U timeout,
INT8U *perr)
{
void *pmsg;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#ifdef OS_SAFETY_CRITICAL
if (perr == (INT8U *)0) {
OS_SAFETY_CRITICAL_EXCEPTION();
return ((void *)0);
}
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*perr = OS_ERR_PEVENT_NULL;
return ((void *)0);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
*perr = OS_ERR_EVENT_TYPE;
return ((void *)0);
}
if (OSIntNesting > 0u) { /* See if called from ISR ... */
*perr = OS_ERR_PEND_ISR; /* ... can't PEND from an ISR */
return ((void *)0);
}
if (OSLockNesting > 0u) { /* See if called with scheduler locked ... */
*perr = OS_ERR_PEND_LOCKED; /* ... can't PEND when locked */
return ((void *)0);
}
OS_ENTER_CRITICAL();
pmsg = pevent->OSEventPtr;
if (pmsg != (void *)0) { /* See if there is already a message */
pevent->OSEventPtr = (void *)0; /* Clear the mailbox */
OS_EXIT_CRITICAL();
*perr = OS_ERR_NONE;
return (pmsg); /* Return the message received (or NULL) */
}
OSTCBCur->OSTCBStat |= OS_STAT_MBOX; /* Message not available, task will pend */
OSTCBCur->OSTCBStatPend = OS_STAT_PEND_OK;
OSTCBCur->OSTCBDly = timeout; /* Load timeout in TCB */
OS_EventTaskWait(pevent); /* Suspend task until event or timeout occurs */
OS_EXIT_CRITICAL();
OS_Sched(); /* Find next highest priority task ready to run */
OS_ENTER_CRITICAL();
switch (OSTCBCur->OSTCBStatPend) { /* See if we timed-out or aborted */
case OS_STAT_PEND_OK:
pmsg = OSTCBCur->OSTCBMsg;
*perr = OS_ERR_NONE;
break;
case OS_STAT_PEND_ABORT:
pmsg = (void *)0;
*perr = OS_ERR_PEND_ABORT; /* Indicate that we aborted */
break;
case OS_STAT_PEND_TO:
default:
OS_EventTaskRemove(OSTCBCur, pevent);
pmsg = (void *)0;
*perr = OS_ERR_TIMEOUT; /* Indicate that we didn't get event within TO */
break;
}
OSTCBCur->OSTCBStat = OS_STAT_RDY; /* Set task status to ready */
OSTCBCur->OSTCBStatPend = OS_STAT_PEND_OK; /* Clear pend status */
OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0; /* Clear event pointers */
#if (OS_EVENT_MULTI_EN > 0u)
OSTCBCur->OSTCBEventMultiPtr = (OS_EVENT **)0;
#endif
OSTCBCur->OSTCBMsg = (void *)0; /* Clear received message */
OS_EXIT_CRITICAL();
return (pmsg); /* Return received message */
}
/*$PAGE*/
/*
*********************************************************************************************************
* ABORT WAITING ON A MESSAGE MAILBOX
*
* Description: This function aborts & readies any tasks currently waiting on a mailbox. This function
* should be used to fault-abort the wait on the mailbox, rather than to normally signal
* the mailbox via OSMboxPost() or OSMboxPostOpt().
*
* Arguments : pevent is a pointer to the event control block associated with the desired mailbox.
*
* opt determines the type of ABORT performed:
* OS_PEND_OPT_NONE ABORT wait for a single task (HPT) waiting on the
* mailbox
* OS_PEND_OPT_BROADCAST ABORT wait for ALL tasks that are waiting on the
* mailbox
*
* perr is a pointer to where an error message will be deposited. Possible error
* messages are:
*
* OS_ERR_NONE No tasks were waiting on the mailbox.
* OS_ERR_PEND_ABORT At least one task waiting on the mailbox was readied
* and informed of the aborted wait; check return value
* for the number of tasks whose wait on the mailbox
* was aborted.
* OS_ERR_EVENT_TYPE If you didn't pass a pointer to a mailbox.
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
*
* Returns : == 0 if no tasks were waiting on the mailbox, or upon error.
* > 0 if one or more tasks waiting on the mailbox are now readied and informed.
*********************************************************************************************************
*/
#if OS_MBOX_PEND_ABORT_EN > 0u
INT8U OSMboxPendAbort (OS_EVENT *pevent,
INT8U opt,
INT8U *perr)
{
INT8U nbr_tasks;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#ifdef OS_SAFETY_CRITICAL
if (perr == (INT8U *)0) {
OS_SAFETY_CRITICAL_EXCEPTION();
return (0u);
}
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*perr = OS_ERR_PEVENT_NULL;
return (0u);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
*perr = OS_ERR_EVENT_TYPE;
return (0u);
}
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0u) { /* See if any task waiting on mailbox? */
nbr_tasks = 0u;
switch (opt) {
case OS_PEND_OPT_BROADCAST: /* Do we need to abort ALL waiting tasks? */
while (pevent->OSEventGrp != 0u) { /* Yes, ready ALL tasks waiting on mailbox */
(void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX, OS_STAT_PEND_ABORT);
nbr_tasks++;
}
break;
case OS_PEND_OPT_NONE:
default: /* No, ready HPT waiting on mailbox */
(void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX, OS_STAT_PEND_ABORT);
nbr_tasks++;
break;
}
OS_EXIT_CRITICAL();
OS_Sched(); /* Find HPT ready to run */
*perr = OS_ERR_PEND_ABORT;
return (nbr_tasks);
}
OS_EXIT_CRITICAL();
*perr = OS_ERR_NONE;
return (0u); /* No tasks waiting on mailbox */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* POST MESSAGE TO A MAILBOX
*
* Description: This function sends a message to a mailbox
*
* Arguments : pevent is a pointer to the event control block associated with the desired mailbox
*
* pmsg is a pointer to the message to send. You MUST NOT send a NULL pointer.
*
* Returns : OS_ERR_NONE The call was successful and the message was sent
* OS_ERR_MBOX_FULL If the mailbox already contains a message. You can can only send one
* message at a time and thus, the message MUST be consumed before you
* are allowed to send another one.
* OS_ERR_EVENT_TYPE If you are attempting to post to a non mailbox.
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer
* OS_ERR_POST_NULL_PTR If you are attempting to post a NULL pointer
*
* Note(s) : 1) HPT means Highest Priority Task
*********************************************************************************************************
*/
#if OS_MBOX_POST_EN > 0u
INT8U OSMboxPost (OS_EVENT *pevent,
void *pmsg)
{
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
return (OS_ERR_PEVENT_NULL);
}
if (pmsg == (void *)0) { /* Make sure we are not posting a NULL pointer */
return (OS_ERR_POST_NULL_PTR);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
return (OS_ERR_EVENT_TYPE);
}
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0u) { /* See if any task pending on mailbox */
/* Ready HPT waiting on event */
(void)OS_EventTaskRdy(pevent, pmsg, OS_STAT_MBOX, OS_STAT_PEND_OK);
OS_EXIT_CRITICAL();
OS_Sched(); /* Find highest priority task ready to run */
return (OS_ERR_NONE);
}
if (pevent->OSEventPtr != (void *)0) { /* Make sure mailbox doesn't already have a msg */
OS_EXIT_CRITICAL();
return (OS_ERR_MBOX_FULL);
}
pevent->OSEventPtr = pmsg; /* Place message in mailbox */
OS_EXIT_CRITICAL();
return (OS_ERR_NONE);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* POST MESSAGE TO A MAILBOX
*
* Description: This function sends a message to a mailbox
*
* Arguments : pevent is a pointer to the event control block associated with the desired mailbox
*
* pmsg is a pointer to the message to send. You MUST NOT send a NULL pointer.
*
* opt determines the type of POST performed:
* OS_POST_OPT_NONE POST to a single waiting task
* (Identical to OSMboxPost())
* OS_POST_OPT_BROADCAST POST to ALL tasks that are waiting on the mailbox
*
* OS_POST_OPT_NO_SCHED Indicates that the scheduler will NOT be invoked
*
* Returns : OS_ERR_NONE The call was successful and the message was sent
* OS_ERR_MBOX_FULL If the mailbox already contains a message. You can can only send one
* message at a time and thus, the message MUST be consumed before you
* are allowed to send another one.
* OS_ERR_EVENT_TYPE If you are attempting to post to a non mailbox.
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer
* OS_ERR_POST_NULL_PTR If you are attempting to post a NULL pointer
*
* Note(s) : 1) HPT means Highest Priority Task
*
* Warning : Interrupts can be disabled for a long time if you do a 'broadcast'. In fact, the
* interrupt disable time is proportional to the number of tasks waiting on the mailbox.
*********************************************************************************************************
*/
#if OS_MBOX_POST_OPT_EN > 0u
INT8U OSMboxPostOpt (OS_EVENT *pevent,
void *pmsg,
INT8U opt)
{
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
return (OS_ERR_PEVENT_NULL);
}
if (pmsg == (void *)0) { /* Make sure we are not posting a NULL pointer */
return (OS_ERR_POST_NULL_PTR);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
return (OS_ERR_EVENT_TYPE);
}
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0u) { /* See if any task pending on mailbox */
if ((opt & OS_POST_OPT_BROADCAST) != 0x00u) { /* Do we need to post msg to ALL waiting tasks ? */
while (pevent->OSEventGrp != 0u) { /* Yes, Post to ALL tasks waiting on mailbox */
(void)OS_EventTaskRdy(pevent, pmsg, OS_STAT_MBOX, OS_STAT_PEND_OK);
}
} else { /* No, Post to HPT waiting on mbox */
(void)OS_EventTaskRdy(pevent, pmsg, OS_STAT_MBOX, OS_STAT_PEND_OK);
}
OS_EXIT_CRITICAL();
if ((opt & OS_POST_OPT_NO_SCHED) == 0u) { /* See if scheduler needs to be invoked */
OS_Sched(); /* Find HPT ready to run */
}
return (OS_ERR_NONE);
}
if (pevent->OSEventPtr != (void *)0) { /* Make sure mailbox doesn't already have a msg */
OS_EXIT_CRITICAL();
return (OS_ERR_MBOX_FULL);
}
pevent->OSEventPtr = pmsg; /* Place message in mailbox */
OS_EXIT_CRITICAL();
return (OS_ERR_NONE);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* QUERY A MESSAGE MAILBOX
*
* Description: This function obtains information about a message mailbox.
*
* Arguments : pevent is a pointer to the event control block associated with the desired mailbox
*
* p_mbox_data is a pointer to a structure that will contain information about the message
* mailbox.
*
* Returns : OS_ERR_NONE The call was successful and the message was sent
* OS_ERR_EVENT_TYPE If you are attempting to obtain data from a non mailbox.
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer
* OS_ERR_PDATA_NULL If 'p_mbox_data' is a NULL pointer
*********************************************************************************************************
*/
#if OS_MBOX_QUERY_EN > 0u
INT8U OSMboxQuery (OS_EVENT *pevent,
OS_MBOX_DATA *p_mbox_data)
{
INT8U i;
OS_PRIO *psrc;
OS_PRIO *pdest;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
return (OS_ERR_PEVENT_NULL);
}
if (p_mbox_data == (OS_MBOX_DATA *)0) { /* Validate 'p_mbox_data' */
return (OS_ERR_PDATA_NULL);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
return (OS_ERR_EVENT_TYPE);
}
OS_ENTER_CRITICAL();
p_mbox_data->OSEventGrp = pevent->OSEventGrp; /* Copy message mailbox wait list */
psrc = &pevent->OSEventTbl[0];
pdest = &p_mbox_data->OSEventTbl[0];
for (i = 0u; i < OS_EVENT_TBL_SIZE; i++) {
*pdest++ = *psrc++;
}
p_mbox_data->OSMsg = pevent->OSEventPtr; /* Get message from mailbox */
OS_EXIT_CRITICAL();
return (OS_ERR_NONE);
}
#endif /* OS_MBOX_QUERY_EN */
#endif /* OS_MBOX_EN */
uC/OS-II 函数之邮箱管理相关函数的更多相关文章
- uC/OS II 函数说明 之–OSTaskCreate()与OSTaskCreateExt()
1. OSTaskCreate() OSTaskCreate()建立一个新任务,能够在多任务环境启动之前,或者执行任务中建立任务.注意,ISR中禁止建立任务,一个任务必须为无限循环结构. ...
- uC/OS II原理分析及源码阅读（一）
uC/OS II(Micro Control Operation System Two)是一个可以基于ROM运行的.可裁减的.抢占式.实时多任务内核,具有高度可移植性,特别适合于微处理器和控制器,是和 ...
- 【原创】uC/OS II 任务切换原理
今天学习了uC/OS II的任务切换,知道要实现任务的切换,要将原先任务的寄存器压入任务堆栈,再将新任务中任务堆栈的寄存器内容弹出到CPU的寄存器,其中的CS.IP寄存器没有出栈和入栈指令,所以只能引 ...
- 【小梅哥SOPC学习笔记】NIOS II处理器运行UC/OS II
SOPC开发流程之NIOS II 处理器运行 UC/OS II 这里以在芯航线FPGA学习套件的核心板上搭建 NIOS II 软核并运行 UCOS II操作系统为例介绍SOPC的开发流程. 第一步:建 ...
- uC/OS-II 函数之内存管理相关函数
上文主要介绍了邮箱管理相关的函数,本文介绍内存管理相关的函数:OSMemCreate()内存块创建函数,OSMemGet()函数,OSMemPut()函数,OSMemQuery()函数.以前用过的uC ...
- uC/OS-II 一些函数简介
获得更多资料欢迎进入我的网站或者 csdn或者博客园 以前搞硬件的经验,最近突然翻出来了.分享给大家:主要讲解uC/OS-II常用函数:虽说现在转行软件了,但是感觉之前搞硬件的经验还真是很有用对于理解 ...
- uc/os iii移植到STM32F4---IAR开发环境
也许是先入为主的原因,时钟用不惯Keil环境,大多数的教程都是拿keil写的,尝试将官方的uc/os iii 移植到IAR环境. 1.首先尝试从官网上下载的官方移植的代码,编译通过,但是执行会报堆栈溢 ...
- uC/OS-III 时钟节拍，时间管理，时间片调度
uC/OS-III 时钟节拍,时间管理,时间片调度 时钟节拍 时钟节拍可谓是 uC/OS 操作系统的心脏,它若不跳动,整个系统都将会瘫痪. 时钟节拍就是操作系统的时基,操作系统要实现时间上的管理, ...
- uc/os任务创建
问题描述: uc/os中任务创建 问题解决: 创建一个任务,任务从无到有.任务创建函数分两种, 一种是基本的创建函数OSTaskCreate, 另一种是扩展的任务创建函数OSTaskCrea ...
随机推荐
- 新做的系统，第一次拉maven项目时，鼠标左键+ctrl键不能进方法
对项目选择属性,跳转至:选择以下步骤
- 3-为什么很多 对 1e9+7(100000007)取模
首先有很多题目的答案是很大的,然而出题人的本意也不是让选手写高精度或者Java,所以势必要让答案落在整型的范围内.那么怎么做到这一点呢,对一个很大的质数取模即可(自行思考为什么不是小数).那么如果您学 ...
- LoadRunner11学习记录三 -- 迭代和并发
LoadRunner中%d和%s是什么意思? %d 格式化输出短整形数据,TC环境中占用两个字节,输出整数范围为:32768~32767.Visual C++环境中占用四个字节,输出数据范围为:-21 ...
- vnpy自动化交易
c++ python 写的自动化交易平台 期货ctp
- json操作工具-LitJson
LitJSON是json生成与读取的操作工具,使用很方便并且网上还能找到源码.下面是使用LitJSON的例子: 一.生成json:实例化一个JsonData,然后按照List数组的方式向里面填. Js ...
- paho_c_pub 使用方法
Latest Paho Status (2) 摘自:http://modelbasedtesting.co.uk/ I last wrote about the state of Paho in Oc ...
- JDBC 连接 MySQL 时碰到的小坑
最近从MS SQL Server换到了MySQL,已经是8.11版本了,安装的时候似乎还用了新的身份认证方式之类的,连接过程中也是磕磕绊绊,碰到很多奇奇怪怪的问题,在此记录下来. 驱动加载: 以前使用 ...
- xStream完美转换XML、JSON(转）
xStream框架 xStream可以轻易的将Java对象和xml文档相互转换,而且可以修改某个特定的属性和节点名称,而且也支持json的转换: 前面有介绍过json-lib这个框架,在线博文:htt ...
- sql insert、update、delete完以后返回主键ID
以前只用过在insert完以后利用select @@IDENTITY返回主键ID,最近在做微信公众平台,遇到一个需求是在帮绑定万微信openid后自动完成登陆,这就需要update以后返回主键ID,查 ...
- HttpUploader6-queue版本更新说明
HttpUploader6-queue版本更新说明 博客园:http://www.cnblogs.com/xproer/p/5109761.html 网易博客:http://hyhyo.blog.16 ...