argp_parseThe default behavior of argp_parse is designed to be convenient
for the most common case of parsing program command line argument. To
modify these defaults, the following flags may be or’d together in the
flags argument to argp_parse:
ARGP_PARSE_ARGV0 ¶Don’t ignore the first element of the argv argument to
argp_parse. Unless ARGP_NO_ERRS is set, the first element
of the argument vector is skipped for option parsing purposes, as it
corresponds to the program name in a command line.
ARGP_NO_ERRS ¶Don’t print error messages for unknown options to stderr; unless
this flag is set, ARGP_PARSE_ARGV0 is ignored, as argv[0]
is used as the program name in the error messages. This flag implies
ARGP_NO_EXIT. This is based on the assumption that silent exiting
upon errors is bad behavior.
ARGP_NO_ARGS ¶Don’t parse any non-option args. Normally these are parsed by calling
the parse functions with a key of ARGP_KEY_ARG, the actual
argument being the value. This flag needn’t normally be set, as the
default behavior is to stop parsing as soon as an argument fails to be
parsed. See Argp Parser Functions.
ARGP_IN_ORDER ¶Parse options and arguments in the same order they occur on the command line. Normally they’re rearranged so that all options come first.
ARGP_NO_HELP ¶Don’t provide the standard long option ‘--help’, which ordinarily
causes usage and option help information to be output to stdout
and exit (0).
ARGP_NO_EXIT ¶Don’t exit on errors, although they may still result in error messages.
ARGP_LONG_ONLY ¶Use the GNU getopt ‘long-only’ rules for parsing arguments. This allows long-options to be recognized with only a single ‘-’ (i.e., ‘-help’). This results in a less useful interface, and its use is discouraged as it conflicts with the way most GNU programs work as well as the GNU coding standards.
ARGP_SILENT ¶Turns off any message-printing/exiting options, specifically
ARGP_NO_EXIT, ARGP_NO_ERRS, and ARGP_NO_HELP.