2 FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
7 This file is part of the FreeRTOS distribution.
9 FreeRTOS is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License (version 2) as published by the
11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
13 ***************************************************************************
14 >>! NOTE: The modification to the GPL is included to allow you to !<<
15 >>! distribute a combined work that includes FreeRTOS without being !<<
16 >>! obliged to provide the source code for proprietary components !<<
17 >>! outside of the FreeRTOS kernel. !<<
18 ***************************************************************************
20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
23 link: http://www.freertos.org/a00114.html
25 ***************************************************************************
27 * FreeRTOS provides completely free yet professionally developed, *
28 * robust, strictly quality controlled, supported, and cross *
29 * platform software that is more than just the market leader, it *
30 * is the industry's de facto standard. *
32 * Help yourself get started quickly while simultaneously helping *
33 * to support the FreeRTOS project by purchasing a FreeRTOS *
34 * tutorial book, reference manual, or both: *
35 * http://www.FreeRTOS.org/Documentation *
37 ***************************************************************************
39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
40 the FAQ page "My application does not run, what could be wrong?". Have you
41 defined configASSERT()?
43 http://www.FreeRTOS.org/support - In return for receiving this top quality
44 embedded software for free we request you assist our global community by
45 participating in the support forum.
47 http://www.FreeRTOS.org/training - Investing in training allows your team to
48 be as productive as possible as early as possible. Now you can receive
49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
50 Ltd, and the world's leading authority on the world's leading RTOS.
52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
61 licenses offer ticketed support, indemnification and commercial middleware.
63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
64 engineered and independently SIL3 certified version for use in safety and
65 mission critical applications that require provable dependability.
71 * Create a single persistent task which periodically dynamically creates another
72 * two tasks. The original task is called the creator task, the two tasks it
73 * creates are called suicidal tasks.
75 * One of the created suicidal tasks kill one other suicidal task before killing
76 * itself - leaving just the original task remaining.
78 * The creator task must be spawned after all of the other demo application tasks
79 * as it keeps a check on the number of tasks under the scheduler control. The
80 * number of tasks it expects to see running should never be greater than the
81 * number of tasks that were in existence when the creator task was spawned, plus
82 * one set of four suicidal tasks. If this number is exceeded an error is flagged.
84 * \page DeathC death.c
92 /* Scheduler include files. */
96 /* Demo program include files. */
99 #define deathSTACK_SIZE ( configMINIMAL_STACK_SIZE + 60 )
101 /* The task originally created which is responsible for periodically dynamically
102 creating another four tasks. */
103 static portTASK_FUNCTION_PROTO( vCreateTasks, pvParameters );
105 /* The task function of the dynamically created tasks. */
106 static portTASK_FUNCTION_PROTO( vSuicidalTask, pvParameters );
108 /* A variable which is incremented every time the dynamic tasks are created. This
109 is used to check that the task is still running. */
110 static volatile uint16_t usCreationCount = 0;
112 /* Used to store the number of tasks that were originally running so the creator
113 task can tell if any of the suicidal tasks have failed to die.
115 static volatile UBaseType_t uxTasksRunningAtStart = 0;
117 /* When a task deletes itself, it stack and TCB are cleaned up by the Idle task.
118 Under heavy load the idle task might not get much processing time, so it would
119 be legitimate for several tasks to remain undeleted for a short period. There
120 may also be a few other unexpected tasks if, for example, the tasks that test
121 static allocation are also being used. */
122 static const UBaseType_t uxMaxNumberOfExtraTasksRunning = 3;
124 /* Used to store a handle to the task that should be killed by a suicidal task,
125 before it kills itself. */
126 TaskHandle_t xCreatedTask;
128 /*-----------------------------------------------------------*/
130 void vCreateSuicidalTasks( UBaseType_t uxPriority )
132 xTaskCreate( vCreateTasks, "CREATOR", deathSTACK_SIZE, ( void * ) NULL, uxPriority, NULL );
134 /* Record the number of tasks that are running now so we know if any of the
135 suicidal tasks have failed to be killed. */
136 uxTasksRunningAtStart = ( UBaseType_t ) uxTaskGetNumberOfTasks();
138 /* FreeRTOS.org versions before V3.0 started the idle-task as the very
139 first task. The idle task was then already included in uxTasksRunningAtStart.
140 From FreeRTOS V3.0 on, the idle task is started when the scheduler is
141 started. Therefore the idle task is not yet accounted for. We correct
142 this by increasing uxTasksRunningAtStart by 1. */
143 uxTasksRunningAtStart++;
145 /* From FreeRTOS version 7.0.0 can optionally create a timer service task.
146 If this is done, then uxTasksRunningAtStart needs incrementing again as that
147 too is created when the scheduler is started. */
148 #if configUSE_TIMERS == 1
150 uxTasksRunningAtStart++;
154 /*-----------------------------------------------------------*/
156 static portTASK_FUNCTION( vSuicidalTask, pvParameters )
158 volatile long l1, l2;
159 TaskHandle_t xTaskToKill;
160 const TickType_t xDelay = pdMS_TO_TICKS( ( TickType_t ) 200 );
162 if( pvParameters != NULL )
164 /* This task is periodically created four times. Two created tasks are
165 passed a handle to the other task so it can kill it before killing itself.
166 The other task is passed in null. */
167 xTaskToKill = *( TaskHandle_t* )pvParameters;
176 /* Do something random just to use some stack and registers. */
180 vTaskDelay( xDelay );
182 if( xTaskToKill != NULL )
184 /* Make sure the other task has a go before we delete it. */
185 vTaskDelay( ( TickType_t ) 0 );
187 /* Kill the other task that was created by vCreateTasks(). */
188 vTaskDelete( xTaskToKill );
190 /* Kill ourselves. */
194 }/*lint !e818 !e550 Function prototype must be as per standard for task functions. */
195 /*-----------------------------------------------------------*/
197 static portTASK_FUNCTION( vCreateTasks, pvParameters )
199 const TickType_t xDelay = pdMS_TO_TICKS( ( TickType_t ) 1000 );
200 UBaseType_t uxPriority;
202 /* Remove compiler warning about unused parameter. */
203 ( void ) pvParameters;
205 uxPriority = uxTaskPriorityGet( NULL );
209 /* Just loop round, delaying then creating the four suicidal tasks. */
210 vTaskDelay( xDelay );
214 xTaskCreate( vSuicidalTask, "SUICID1", configMINIMAL_STACK_SIZE, NULL, uxPriority, &xCreatedTask );
215 xTaskCreate( vSuicidalTask, "SUICID2", configMINIMAL_STACK_SIZE, &xCreatedTask, uxPriority, NULL );
220 /*-----------------------------------------------------------*/
222 /* This is called to check that the creator task is still running and that there
223 are not any more than four extra tasks. */
224 BaseType_t xIsCreateTaskStillRunning( void )
226 static uint16_t usLastCreationCount = 0xfff;
227 BaseType_t xReturn = pdTRUE;
228 static UBaseType_t uxTasksRunningNow;
230 if( usLastCreationCount == usCreationCount )
236 usLastCreationCount = usCreationCount;
239 uxTasksRunningNow = ( UBaseType_t ) uxTaskGetNumberOfTasks();
241 if( uxTasksRunningNow < uxTasksRunningAtStart )
245 else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )
251 /* Everything is okay. */