NAME

       egd_channel_info - Get various information about a particular channel

SYNOPSIS

       #include <eegdev.h>

       int egd_channel_info(const struct eegdev* dev, int stype,
                             unsigned int index, int fieldtype, ...);

DESCRIPTION

       egd_channel_info()  provides  different  type  of information about the channel at the index index of the
       group specified by stype of the device referenced  by  dev.  As  described  for  egd_acq_setup(3),  stype
       specifies the type of channel. It must one of the values returned by egd_sensor_type(3).

       The  information  returned  by  the  function  is  defined by the variable list of argument. This list is
       composed of successive couple grouping one field type identifier specifying the feature to be get  and  a
       pointer to a value whose type depends on the previous field type. The list must finish by EGD_END.

       The  field  identifers  can  be  the  following  (The  expected corresponding pointer type is provided in
       parenthesis):

       EGD_LABEL (char*)
              Name of the channel. The pointed array should be long enough to hold 32 characters (including  the
              null termination character).

       EGD_ISINT (int*)
              Indicates  whether the data provided by the channel are integer or floating point. (zero indicates
              floating point, non-zero indicates integer).

       EGD_MM_I (int32_t*)
              Returns in an array of 2 int32_t the minimal and maximal values that the channel can  deliver  (If
              the channel deliver floating point data, these values can be underestimated due to overflow)

       EGD_MM_F (float*)
              Returns  in an array of 2 float values the minimal and maximal values that the channel can deliver
              (If the channel deliver double floating point data, these values  can  be  underestimated  due  to
              overflow)

       EGD_MM_D (double*)
              Returns  in  an  array  of  2  double  values  the minimal and maximal values that the channel can
              deliver.

       EGD_UNIT (char*)
              Unit in which the channel data is expressed. The pointed array should be long enough  to  hold  16
              characters (including the null termination character).

       EGD_TRANSDUCTER (char*)
              Transducter  type  of  the  sensor. The pointed array should be long enough to hold 128 characters
              (including the null termination character).

       EGD_PREFILTERING (char*)
              Information about the filters already applied on data. The pointed array should be long enough  to
              hold 128 characters (including the null termination character).

RETURN VALUE

       The function returns 0 in case of succes. Otherwise, -1 is returned and errno is set accordingly.

ERRORS

       egd_channel_info() will fail if:

       EINVAL dev  is  NULL, stype is an invalid sensor type, index is bigger than the maximal number of channel
              in the group, any field identifier is unknown or any pointer used is NULL.

THREAD SAFETY

       egd_channel_info() is thread-safe.

SEE ALSO

       egd_acq_setup(3), egd_sensor_type(3)

EPFL                                                  2010                                   EGD_CHANNEL_INFO(3)