2 FreeRTOS.org V4.2.0 - Copyright (C) 2003-2007 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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34 * Create a single persistent task which periodically dynamically creates another
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35 * four tasks. The original task is called the creator task, the four tasks it
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36 * creates are called suicidal tasks.
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38 * Two of the created suicidal tasks kill one other suicidal task before killing
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39 * themselves - leaving just the original task remaining.
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41 * The creator task must be spawned after all of the other demo application tasks
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42 * as it keeps a check on the number of tasks under the scheduler control. The
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43 * number of tasks it expects to see running should never be greater than the
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44 * number of tasks that were in existence when the creator task was spawned, plus
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45 * one set of four suicidal tasks. If this number is exceeded an error is flagged.
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47 * \page DeathC death.c
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48 * \ingroup DemoFiles
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54 + CreationCount sizes changed from unsigned portBASE_TYPE to
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55 unsigned portSHORT to minimize the risk of overflowing.
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57 + Reset of usLastCreationCount added
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60 + Changed the dummy calculation to use variables of type long, rather than
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61 float. This allows the file to be used with ports that do not support
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68 /* Scheduler include files. */
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69 #include "FreeRTOS.h"
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72 /* Demo program include files. */
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75 #define deathSTACK_SIZE ( configMINIMAL_STACK_SIZE + 24 )
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77 /* The task originally created which is responsible for periodically dynamically
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78 creating another four tasks. */
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79 static portTASK_FUNCTION_PROTO( vCreateTasks, pvParameters );
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81 /* The task function of the dynamically created tasks. */
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82 static portTASK_FUNCTION_PROTO( vSuicidalTask, pvParameters );
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84 /* A variable which is incremented every time the dynamic tasks are created. This
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85 is used to check that the task is still running. */
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86 static volatile unsigned portSHORT usCreationCount = 0;
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88 /* Used to store the number of tasks that were originally running so the creator
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89 task can tell if any of the suicidal tasks have failed to die.
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91 static volatile unsigned portBASE_TYPE uxTasksRunningAtStart = 0;
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93 /* Tasks are deleted by the idle task. Under heavy load the idle task might
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94 not get much processing time, so it would be legitimate for several tasks to
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95 remain undeleted for a short period. */
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96 static const unsigned portBASE_TYPE uxMaxNumberOfExtraTasksRunning = 4;
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98 /* Used to store a handle to the tasks that should be killed by a suicidal task,
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99 before it kills itself. */
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100 xTaskHandle xCreatedTask1, xCreatedTask2;
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102 /*-----------------------------------------------------------*/
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104 void vCreateSuicidalTasks( unsigned portBASE_TYPE uxPriority )
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106 unsigned portBASE_TYPE *puxPriority;
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108 /* Create the Creator tasks - passing in as a parameter the priority at which
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109 the suicidal tasks should be created. */
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110 puxPriority = ( unsigned portBASE_TYPE * ) pvPortMalloc( sizeof( unsigned portBASE_TYPE ) );
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111 *puxPriority = uxPriority;
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113 xTaskCreate( vCreateTasks, ( signed portCHAR * ) "CREATOR", deathSTACK_SIZE, ( void * ) puxPriority, uxPriority, NULL );
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115 /* Record the number of tasks that are running now so we know if any of the
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116 suicidal tasks have failed to be killed. */
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117 uxTasksRunningAtStart = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks();
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119 /* FreeRTOS.org versions before V3.0 started the idle-task as the very
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120 first task. The idle task was then already included in uxTasksRunningAtStart.
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121 From FreeRTOS V3.0 on, the idle task is started when the scheduler is
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122 started. Therefore the idle task is not yet accounted for. We correct
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123 this by increasing uxTasksRunningAtStart by 1. */
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124 uxTasksRunningAtStart++;
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126 /*-----------------------------------------------------------*/
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128 static portTASK_FUNCTION( vSuicidalTask, pvParameters )
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130 volatile portLONG l1, l2;
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131 xTaskHandle xTaskToKill;
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132 const portTickType xDelay = ( portTickType ) 200 / portTICK_RATE_MS;
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134 if( pvParameters != NULL )
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136 /* This task is periodically created four times. Two created tasks are
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137 passed a handle to the other task so it can kill it before killing itself.
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138 The other task is passed in null. */
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139 xTaskToKill = *( xTaskHandle* )pvParameters;
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143 xTaskToKill = NULL;
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148 /* Do something random just to use some stack and registers. */
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152 vTaskDelay( xDelay );
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154 if( xTaskToKill != NULL )
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156 /* Make sure the other task has a go before we delete it. */
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157 vTaskDelay( ( portTickType ) 0 );
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158 /* Kill the other task that was created by vCreateTasks(). */
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159 vTaskDelete( xTaskToKill );
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160 /* Kill ourselves. */
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161 vTaskDelete( NULL );
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164 }/*lint !e818 !e550 Function prototype must be as per standard for task functions. */
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165 /*-----------------------------------------------------------*/
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167 static portTASK_FUNCTION( vCreateTasks, pvParameters )
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169 const portTickType xDelay = ( portTickType ) 1000 / portTICK_RATE_MS;
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170 unsigned portBASE_TYPE uxPriority;
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172 uxPriority = *( unsigned portBASE_TYPE * ) pvParameters;
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173 vPortFree( pvParameters );
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177 /* Just loop round, delaying then creating the four suicidal tasks. */
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178 vTaskDelay( xDelay );
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180 xTaskCreate( vSuicidalTask, ( signed portCHAR * ) "SUICID1", deathSTACK_SIZE, NULL, uxPriority, &xCreatedTask1 );
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181 xTaskCreate( vSuicidalTask, ( signed portCHAR * ) "SUICID2", deathSTACK_SIZE, &xCreatedTask1, uxPriority, NULL );
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183 xTaskCreate( vSuicidalTask, ( signed portCHAR * ) "SUICID1", deathSTACK_SIZE, NULL, uxPriority, &xCreatedTask2 );
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184 xTaskCreate( vSuicidalTask, ( signed portCHAR * ) "SUICID2", deathSTACK_SIZE, &xCreatedTask2, uxPriority, NULL );
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189 /*-----------------------------------------------------------*/
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191 /* This is called to check that the creator task is still running and that there
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192 are not any more than four extra tasks. */
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193 portBASE_TYPE xIsCreateTaskStillRunning( void )
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195 static portSHORT usLastCreationCount = -1;
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196 portBASE_TYPE xReturn = pdTRUE;
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197 static unsigned portBASE_TYPE uxTasksRunningNow;
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199 if( usLastCreationCount == usCreationCount )
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205 usLastCreationCount = usCreationCount;
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208 uxTasksRunningNow = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks();
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210 if( uxTasksRunningNow < uxTasksRunningAtStart )
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214 else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )
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220 /* Everything is okay. */
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