stv0g/comedilib
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added some error checks

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This commit is contained in:
Frank Mori Hess 2005-02-24 20:46:56 +00:00
parent e3c958cf65
commit 545b9420d5
1 changed files with 25 additions and 3 deletions
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28
demo/tut2.c
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@ -16,6 +16,7 @@ int subdev = 0; /* change this to your input subdevice */
int chan = 0; /* change this to your channel */
int range = 0; /* more on this later */
int aref = AREF_GROUND; /* more on this later */
const char filename[] = "/dev/comedi0";
int main(int argc, char *argv[])
{
@ -24,11 +25,32 @@ int main(int argc, char *argv[])
int maxdata;
double volts;
comedi_range *cr;
cf = comedi_open("/dev/comedi0");
int retval;
cf = comedi_open(filename);
if(cf == NULL)
{
comedi_perror(filename);
return 1;
}
maxdata = comedi_get_maxdata(cf, subdev, chan);
if(maxdata == 0)
{
comedi_perror(filename);
return 1;
}
cr = comedi_get_range(cf, subdev, chan, range);
comedi_data_read(cf, subdev, chan, range, aref, &data);
if(cr == NULL)
{
comedi_perror(filename);
return 1;
}
retval = comedi_data_read(cf, subdev, chan, range, aref, &data);
if(retval < 0)
{
comedi_perror(filename);
return 1;
}
volts = comedi_to_phys(data, cr, maxdata);
printf("%d %g\n", data, volts);