source: multiio/pcmmio/original/dacout.c

/* dacout.c WinSystems PCM-MIO driver Demonstration Program
*
*  $Id$
*
* Compile for GNU/Linux with:
*
*   gcc dacout.c mio_io.o -o dacout
*
*
* This extremely simple program uses the set_dac_voltage function to update
*  the dac output to a specific voltage.
*/

#include <stdio.h>
#include <stdlib.h>
#include "mio_io.h"

main(int argc, char *argv[])
{
int channel = 0;
float voltage;

        /* We must have arguments for channel and voltage */

        if(argc != 3)
        {
                printf("usage : dacout channel voltage\n");
                exit(1);
        }


        /* Channel is the first argument. We'll let the driver
           check for valid channel numbers just to show how the
           mio_error_string works
   */
        channel = atoi(argv[1]);

        /* The same goes for the voltage argument. The driver will tell us
           if the input is out of range
   */

        voltage = atof(argv[2]);

        printf("Setting DAC channel %d to %9.5f Volts\n",channel,voltage);

        set_dac_voltage(channel, voltage);


        /* Here's where any problems with the input parameters will be determined.
           by checking mio_error_code for a non-zero value we can detect error
           conditions.
   */

        if(mio_error_code)
        {
                /* We'll print out the error and exit */

                printf("%s\n",mio_error_string);
                exit(1);
        }

}