* There are basically two forms of options:
'Short options' consist of one dash (`-`) and one alphanumeric
character.
- 'Long options' begin with two dashes (`\--`) and some
+ 'Long options' begin with two dashes (`--`) and some
alphanumeric characters.
* Options are case-sensitive.
* 'sticked' and 'separate form' of options with arguments.
`-oArg` is sticked, `-o Arg` is separate form.
- `\--option=Arg` is sticked, `\--option Arg` is separate form.
+ `--option=Arg` is sticked, `--option Arg` is separate form.
* Long options may be 'abbreviated', as long as the abbreviation
is unambiguous.
* Short options may be bundled, e.g. `-a -b` can be specified as `-ab`.
* Boolean long options can be 'negated' (or 'unset') by prepending
- `no-`, e.g. `\--no-abbrev` instead of `\--abbrev`.
+ `no-`, e.g. `--no-abbrev` instead of `--abbrev`. Conversely,
+ options that begin with `no-` can be 'negated' by removing it.
-* Options and non-option arguments can clearly be separated using the `\--`
- option, e.g. `-a -b \--option \-- \--this-is-a-file` indicates that
- `\--this-is-a-file` must not be processed as an option.
+* Options and non-option arguments can clearly be separated using the `--`
+ option, e.g. `-a -b --option -- --this-is-a-file` indicates that
+ `--this-is-a-file` must not be processed as an option.
Steps to parse options
----------------------
Flags are the bitwise-or of:
`PARSE_OPT_KEEP_DASHDASH`::
- Keep the `\--` that usually separates options from
+ Keep the `--` that usually separates options from
non-option arguments.
`PARSE_OPT_STOP_AT_NON_OPTION`::
There are some macros to easily define options:
`OPT__ABBREV(&int_var)`::
- Add `\--abbrev[=<n>]`.
+ Add `--abbrev[=<n>]`.
-`OPT__DRY_RUN(&int_var)`::
- Add `-n, \--dry-run`.
+`OPT__COLOR(&int_var, description)`::
+ Add `--color[=<when>]` and `--no-color`.
-`OPT__QUIET(&int_var)`::
- Add `-q, \--quiet`.
+`OPT__DRY_RUN(&int_var, description)`::
+ Add `-n, --dry-run`.
-`OPT__VERBOSE(&int_var)`::
- Add `-v, \--verbose`.
+`OPT__FORCE(&int_var, description)`::
+ Add `-f, --force`.
+
+`OPT__QUIET(&int_var, description)`::
+ Add `-q, --quiet`.
+
+`OPT__VERBOSE(&int_var, description)`::
+ Add `-v, --verbose`.
`OPT_GROUP(description)`::
Start an option group. `description` is a short string that
describes the group or an empty string.
Start the description with an upper-case letter.
-`OPT_BOOLEAN(short, long, &int_var, description)`::
- Introduce a boolean option.
- `int_var` is incremented on each use.
+`OPT_BOOL(short, long, &int_var, description)`::
+ Introduce a boolean option. `int_var` is set to one with
+ `--option` and set to zero with `--no-option`.
+
+`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`.
`OPT_BIT(short, long, &int_var, description, mask)`::
Introduce a boolean option.
If used, `int_var` is bitwise-anded with the inverted `mask`.
`OPT_SET_INT(short, long, &int_var, description, integer)`::
- Introduce a boolean option.
- If used, set `int_var` to `integer`.
+ Introduce an integer option.
+ `int_var` is set to `integer` with `--option`, and
+ reset to zero with `--no-option`.
`OPT_SET_PTR(short, long, &ptr_var, description, ptr)`::
Introduce a boolean option.
arguments. Short options that happen to be digits take
precedence over it.
+`OPT_COLOR_FLAG(short, long, &int_var, description)`::
+ Introduce an option that takes an optional argument that can
+ have one of three values: "always", "never", or "auto". If the
+ argument is not given, it defaults to "always". The `--no-` form
+ works like `--long=never`; it cannot take an argument. If
+ "always", set `int_var` to 1; if "never", set `int_var` to 0; if
+ "auto", set `int_var` to 1 if stdout is a tty or a pager,
+ 0 otherwise.
+
+`OPT_NOOP_NOARG(short, long)`::
+ Introduce an option that has no effect and takes no arguments.
+ Use it to hide deprecated options that are still to be recognized
+ and ignored silently.
+
The last element of the array must be `OPT_END()`.
If not stated otherwise, interpret the arguments as follows:
* `short` is a character for the short option
- (e.g. `\'e\'` for `-e`, use `0` to omit),
+ (e.g. `'e'` for `-e`, use `0` to omit),
* `long` is a string for the long option
- (e.g. `"example"` for `\--example`, use `NULL` to omit),
+ (e.g. `"example"` for `--example`, use `NULL` to omit),
* `int_var` is an integer variable,
* Inside `func`, the only interesting member of the structure
given by `opt` is the void pointer `opt->value`.
- `\*opt->value` will be the value that is saved into `var`, if you
+ `*opt->value` will be the value that is saved into `var`, if you
use `OPT_CALLBACK()`.
For example, do `*(unsigned long *)opt->value = 42;` to get 42
into an `unsigned long` variable.