`OPT_COUNTUP(short, long, &int_var, description)`::
Introduce a count-up option.
- `int_var` is incremented on each use of `--option`, and
- reset to zero with `--no-option`.
+ Each use of `--option` increments `int_var`, starting from zero
+ (even if initially negative), and `--no-option` resets it to
+ zero. To determine if `--option` or `--no-option` was encountered at
+ all, initialize `int_var` to a negative value, and if it is still
+ negative after parse_options(), then neither `--option` nor
+ `--no-option` was seen.
`OPT_BIT(short, long, &int_var, description, mask)`::
Introduce a boolean option.
Use it to hide deprecated options that are still to be recognized
and ignored silently.
+`OPT_PASSTHRU(short, long, &char_var, arg_str, description, flags)`::
+ Introduce an option that will be reconstructed into a char* string,
+ which must be initialized to NULL. This is useful when you need to
+ pass the command-line option to another command. Any previous value
+ will be overwritten, so this should only be used for options where
+ the last one specified on the command line wins.
+
+`OPT_PASSTHRU_ARGV(short, long, &argv_array_var, arg_str, description, flags)`::
+ Introduce an option where all instances of it on the command-line will
+ be reconstructed into an argv_array. This is useful when you need to
+ pass the command-line option, which can be specified multiple times,
+ to another command.
+
+`OPT_CMDMODE(short, long, &int_var, description, enum_val)`::
+ Define an "operation mode" option, only one of which in the same
+ group of "operating mode" options that share the same `int_var`
+ can be given by the user. `enum_val` is set to `int_var` when the
+ option is used, but an error is reported if other "operating mode"
+ option has already set its value to the same `int_var`.
+
The last element of the array must be `OPT_END()`.