Demo/Common/Full/print.c

/*
	FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

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	under the terms of the GNU General Public License (version 2) as published
	by the Free Software Foundation and modified by the FreeRTOS exception.

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	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 FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59 
	Temple Place, Suite 330, Boston, MA  02111-1307  USA.

	A special exception to the GPL is included to allow you to distribute a 
	combined work that includes FreeRTOS.org without being obliged to provide
	the source code for any proprietary components.  See the licensing section
	of http://www.FreeRTOS.org for full details.


	***************************************************************************
	*                                                                         *
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	*                                                                         *
	* This is a concise, step by step, 'hands on' guide that describes both   *
	* general multitasking concepts and FreeRTOS specifics. It presents and   *
	* explains numerous examples that are written using the FreeRTOS API.     *
	* Full source code for all the examples is provided in an accompanying    *
	* .zip file.                                                              *
	*                                                                         *
	***************************************************************************

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	Please ensure to read the configuration and relevant port sections of the
	online documentation.

	http://www.FreeRTOS.org - Documentation, latest information, license and
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*/

/**
 * Manages a queue of strings that are waiting to be displayed.  This is used to 
 * ensure mutual exclusion of console output.
 *
 * A task wishing to display a message will call vPrintDisplayMessage (), with a 
 * pointer to the string as the parameter. The pointer is posted onto the 
 * xPrintQueue queue.
 *
 * The task spawned in main. c blocks on xPrintQueue.  When a message becomes 
 * available it calls pcPrintGetNextMessage () to obtain a pointer to the next 
 * string, then uses the functions defined in the portable layer FileIO. c to 
 * display the message.
 *
 * <b>NOTE:</b>
 * Using console IO can disrupt real time performance - depending on the port.  
 * Standard C IO routines are not designed for real time applications.  While 
 * standard IO is useful for demonstration and debugging an alternative method 
 * should be used if you actually require console IO as part of your application.
 *
 * \page PrintC print.c
 * \ingroup DemoFiles
 * <HR>
 */

/*
Changes from V2.0.0

	+ Delay periods are now specified using variables and constants of
	  portTickType rather than unsigned portLONG.
*/

#include <stdlib.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "queue.h"

/* Demo program include files. */
#include "print.h"

static xQueueHandle xPrintQueue;

/*-----------------------------------------------------------*/

void vPrintInitialise( void )
{
const unsigned portBASE_TYPE uxQueueSize = 20;

	/* Create the queue on which errors will be reported. */
	xPrintQueue = xQueueCreate( uxQueueSize, ( unsigned portBASE_TYPE ) sizeof( portCHAR * ) );
}
/*-----------------------------------------------------------*/

void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend )
{
	#ifdef USE_STDIO
		xQueueSend( xPrintQueue, ( void * ) ppcMessageToSend, ( portTickType ) 0 );
	#else
    	/* Stop warnings. */
		( void ) ppcMessageToSend;
	#endif
}
/*-----------------------------------------------------------*/

const portCHAR *pcPrintGetNextMessage( portTickType xPrintRate )
{
portCHAR *pcMessage;

	if( xQueueReceive( xPrintQueue, &pcMessage, xPrintRate ) == pdPASS )
	{
		return pcMessage;
	}
	else
	{
		return NULL;
	}
}