The following flags may be or'd together in the flags field of a
struct argp_option. These flags control various aspects of how
that option is parsed or displayed in help messages:
OPTION_ARG_OPTIONALOPTION_HIDDENOPTION_ALIASname and key from the option being
aliased.
OPTION_DOCIf this flag is set, then the option name field is displayed
unmodified (e.g., no `--' prefix is added) at the left-margin where
a short option would normally be displayed, and this
documentation string is left in it's usual place. For purposes of
sorting, any leading whitespace and punctuation is ignored, unless the
first non-whitespace character is `-'. This entry is displayed
after all options, after OPTION_DOC entries with a leading
`-', in the same group.
OPTION_NO_USAGEargs_doc
field. See Argp Parsers. Including this option in the generic usage
list would be redundant, and should be avoided.
For instance, if args_doc is "FOO BAR\n-x BLAH", and the
`-x' option's purpose is to distinguish these two cases, `-x'
should probably be marked OPTION_NO_USAGE.