Sets the default value or the current value for the feature
    specified by index.

    Format

      #include  <unixlib.h>

      int decc$feature_set_value  (int index, int mode, int value);

1 - Arguments

 index

    An integer value from 0 to the highest allocated feature.

 mode

    An integer indicating whether to set the default or current
    feature value. The values for mode are:

       0 default value
       1 current value

 value

    The feature value to be set.

2 - Description

    The decc$feature_set_value function sets the default value or
    the current value (as determined by the mode argument) for the
    feature specified by index.

    If this function is successful, it returns the previous value.

    On error, -1 is returned and errno is set to indicate the error.

    See also decc$feature_get, decc$feature_get_index, decc$feature_
    get_name, decc$feature_get_value, decc$feature_set, decc$feature_
    show, and decc$feature_show_all.

3 - Return Values

    n                  The previous feature value.
    -1                 Indicates an error; errno is set.