Provided by: libcomedi-dev_0.8.1-5ubuntu6_amd64 bug


       comedi_data_read - read single sample from channel


       #include <comedilib.h>

       int  comedi_data_read  (comedi_t  *  device, unsigned int subdevice, unsigned int channel,
       unsigned int range, unsigned int aref, lsampl_t * data);


       Reads a single sample on the channel specified by the Comedi device device, the  subdevice
       subdevice,  and  the channel channel.  For the A/D conversion (if appropriate), the device
       is configured to use range specification range and (if appropriate) analog reference  type
       aref. Analog reference types that are not supported by the device are silently ignored.

       The function comedi_data_read() reads one data value from the specified channel and places
       the data value in the location pointed to by data.

       WARNING: comedi_data_read() does not do any pausing to allow multiplexed analog inputs  to
       settle  before  performing  an analog to digital conversion.  If you are switching between
       different channels and need to allow your analog input to settle for an accurate  reading,
       use  comedi_data_read_delayed(),  or  set  the  input  channel  at  an  earlier  time with

       On sucess, comedi_data_read() returns 1 (the number of samples  read).   If  there  is  an
       error, -1 is returned.

       Data  values  returned  by  this  function are unsigned integers less than or equal to the
       maximum sample  value  of  the  channel,  which  can  be  determined  using  the  function
       comedi_get_maxdata().  Conversion of data values to physical units can be performed by the
       function comedi_to_phys().

                                         28 October 2007                      COMEDI_DATA_READ(3)