Calls decc$feature_set_value with a character-string feature
    name, rather than an index.

    Format

      #include  <unixlib.h>

      int decc$feature_set  (const char *name, int mode, int value);

1 - Argument

 name

    Pointer to a character string passed as a name in the list of
    supported features.

 mode

    An integer indicating which feature value to return. The values
    for mode are:

       __FEATURE_MODE_DEFVAL        Default value
       __FEATURE_MODE_CURVAL        Current value
       __FEATURE_MODE_MINVAL        Minimum value
       __FEATURE_MODE_MAXVAL        Maximum value
       __FEATURE_MODE_INIT_STATE    Initialization state

 value

    The feature value to be set.

2 - Description

    The decc$feature_set function allows you to call the
    decc$feature_set_value function with a character-string feature
    name, rather than an index into an internal C RTL table.

    If successful, the function returns the previous value.

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

    See also decc$feature_set_value, decc$feature_get, decc$feature_
    get_index, decc$feature_get_name, decc$feature_get_value.
    decc$feature_show, and decc$feature_show_all.

3 - Return Values

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