208 lines
8.4 KiB
C
208 lines
8.4 KiB
C
/*
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* FreeRTOS Kernel V10.2.1
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* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/******************************************************************************
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* NOTE 1: This project provides two demo applications. A simple blinky
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* style project, and a more comprehensive test and demo application. The
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* mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting in main.c is used to select
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* between the two. See the notes on using mainCREATE_SIMPLE_BLINKY_DEMO_ONLY
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* in main.c. This file implements the simply blinky style version.
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*
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* NOTE 2: This file only contains the source code that is specific to the
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* basic demo. Generic functions, such FreeRTOS hook functions, and functions
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* required to configure the hardware are defined in main.c.
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******************************************************************************
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*
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* main_blinky() creates one queue, and two tasks. It then starts the
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* scheduler.
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*
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* The Queue Send Task:
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* The queue send task is implemented by the prvQueueSendTask() function in
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* this file. prvQueueSendTask() sits in a loop that causes it to repeatedly
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* block for 1000 milliseconds, before sending the value 100 to the queue that
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* was created within main_blinky(). Once the value is sent, the task loops
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* back around to block for another 1000 milliseconds...and so on.
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*
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* The Queue Receive Task:
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* The queue receive task is implemented by the prvQueueReceiveTask() function
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* in this file. prvQueueReceiveTask() sits in a loop where it repeatedly
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* blocks on attempts to read data from the queue that was created within
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* main_blinky(). When data is received, the task checks the value of the
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* data, and if the value equals the expected 100, writes 'Blink' to the UART
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* (the UART is used in place of the LED to allow easy execution in QEMU). The
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* 'block time' parameter passed to the queue receive function specifies that
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* the task should be held in the Blocked state indefinitely to wait for data to
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* be available on the queue. The queue receive task will only leave the
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* Blocked state when the queue send task writes to the queue. As the queue
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* send task writes to the queue every 1000 milliseconds, the queue receive
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* task leaves the Blocked state every 1000 milliseconds, and therefore toggles
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* the LED every 200 milliseconds.
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*/
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/* Standard includes. */
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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/* Kernel includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "queue.h"
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extern void PRCI_use_hfxosc(uint32_t);
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/* Priorities used by the tasks. */
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#define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )
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#define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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/* The rate at which data is sent to the queue. The 200ms value is converted
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to ticks using the pdMS_TO_TICKS() macro. */
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#define mainQUEUE_SEND_FREQUENCY_MS pdMS_TO_TICKS( 32 )
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/* The maximum number items the queue can hold. The priority of the receiving
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task is above the priority of the sending task, so the receiving task will
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preempt the sending task and remove the queue items each time the sending task
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writes to the queue. Therefore the queue will never have more than one item in
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it at any time, and even with a queue length of 1, the sending task will never
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find the queue full. */
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#define mainQUEUE_LENGTH ( 1 )
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/*-----------------------------------------------------------*/
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/*
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* Called by main when mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is set to 1 in
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* main.c.
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*/
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void main_blinky( void );
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/*
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* The tasks as described in the comments at the top of this file.
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*/
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static void prvQueueReceiveTask( void *pvParameters );
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static void prvQueueSendTask( void *pvParameters );
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/*-----------------------------------------------------------*/
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/* The queue used by both tasks. */
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static QueueHandle_t xQueue = NULL;
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/*-----------------------------------------------------------*/
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void main_blinky( void )
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{
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PRCI_use_hfxosc(1);
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/* Create the queue. */
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xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( uint32_t ) );
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if( xQueue != NULL )
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{
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/* Start the two tasks as described in the comments at the top of this
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file. */
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xTaskCreate( prvQueueReceiveTask, /* The function that implements the task. */
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"Rx", /* The text name assigned to the task - for debug only as it is not used by the kernel. */
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configMINIMAL_STACK_SIZE * 2U, /* The size of the stack to allocate to the task. */
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NULL, /* The parameter passed to the task - not used in this case. */
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mainQUEUE_RECEIVE_TASK_PRIORITY, /* The priority assigned to the task. */
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NULL ); /* The task handle is not required, so NULL is passed. */
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xTaskCreate( prvQueueSendTask, "TX", configMINIMAL_STACK_SIZE * 2U, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL );
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/* Start the tasks and timer running. */
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vTaskStartScheduler();
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}
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/* If all is well, the scheduler will now be running, and the following
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line will never be reached. If the following line does execute, then
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there was insufficient FreeRTOS heap memory available for the Idle and/or
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timer tasks to be created. See the memory management section on the
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FreeRTOS web site for more details on the FreeRTOS heap
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http://www.freertos.org/a00111.html. */
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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static void prvQueueSendTask( void *pvParameters )
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{
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TickType_t xNextWakeTime;
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const unsigned long ulValueToSend = 100UL;
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BaseType_t xReturned;
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/* Remove compiler warning about unused parameter. */
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( void ) pvParameters;
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/* Initialise xNextWakeTime - this only needs to be done once. */
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xNextWakeTime = xTaskGetTickCount();
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for( ;; )
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{
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/* Place this task in the blocked state until it is time to run again. */
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vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS );
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/* Send to the queue - causing the queue receive task to unblock and
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toggle the LED. 0 is used as the block time so the sending operation
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will not block - it shouldn't need to block as the queue should always
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be empty at this point in the code. */
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xReturned = xQueueSend( xQueue, &ulValueToSend, 0U );
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configASSERT( xReturned == pdPASS );
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}
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}
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/*-----------------------------------------------------------*/
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static void prvQueueReceiveTask( void *pvParameters )
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{
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unsigned long ulReceivedValue;
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const unsigned long ulExpectedValue = 100UL;
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const char * const pcPassMessage = "Blink\r\n";
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const char * const pcFailMessage = "Unexpected value received\r\n";
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/* Remove compiler warning about unused parameter. */
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( void ) pvParameters;
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for( ;; )
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{
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/* Wait until something arrives in the queue - this task will block
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indefinitely provided INCLUDE_vTaskSuspend is set to 1 in
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FreeRTOSConfig.h. */
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xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );
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/* To get here something must have been received from the queue, but
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is it the expected value? If it is, toggle the LED. */
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if( ulReceivedValue == ulExpectedValue )
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{
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write( STDOUT_FILENO, pcPassMessage, strlen( pcPassMessage ) );
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ulReceivedValue = 0U;
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}
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else
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{
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write( STDOUT_FILENO, pcFailMessage, strlen( pcFailMessage ) );
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}
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}
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}
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/*-----------------------------------------------------------*/
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