path: root/Documentation/technical/api-parse-options.txt
diff options
authorJunio C Hamano <>2011-09-27 23:56:49 (GMT)
committerJunio C Hamano <>2011-09-28 00:00:04 (GMT)
commitb04ba2bb42957f63567f530e092385f085b25e63 (patch)
tree995067e56b042a7d4d9df32a50268ef614972737 /Documentation/technical/api-parse-options.txt
parent8d714b11df2b65e5f4272c1616e561930010be90 (diff)
parse-options: deprecate OPT_BOOLEAN
It is natural to expect that an option defined with OPT_BOOLEAN() could be used in this way: int option = -1; /* unspecified */ struct option options[] = { OPT_BOOLEAN(0, "option", &option, "set option"), OPT_END() }; parse_options(ac, av, prefix, options, usage, 0); if (option < 0) ... do the default thing ... else if (!option) ... --no-option was given ... else ... --option was given ... to easily tell three cases apart: - There is no mention of the `--option` on the command line; - The variable is positively set with `--option`; or - The variable is explicitly negated with `--no-option`. Unfortunately, this is not the case. OPT_BOOLEAN() increments the variable every time `--option` is given, and resets it to zero when `--no-option` is given. As a first step to remedy this, introduce a true boolean OPT_BOOL(), and rename OPT_BOOLEAN() to OPT_COUNTUP(). To help transitioning, OPT_BOOLEAN and OPTION_BOOLEAN are defined as deprecated synonyms to OPT_COUNTUP and OPTION_COUNTUP respectively. This is what db7244b (parse-options new features., 2007-11-07) from four years ago started by marking OPTION_BOOLEAN as "INCR would have been a better name". Some existing users do depend on the count-up semantics; for example, users of OPT__VERBOSE() could use it to raise the verbosity level with repeated use of `-v` on the command line, but they probably should be rewritten to use OPT__VERBOSITY() instead these days. I suspect that some users of OPT__FORCE() may also use it to implement different level of forcibleness but I didn't check. On top of this patch, here are the remaining clean-up tasks that other people can help: - Look at each hit in "git grep -e OPT_BOOLEAN"; trace all uses of the value that is set to the underlying variable, and if it can proven that the variable is only used as a boolean, replace it with OPT_BOOL(). If the caller does depend on the count-up semantics, replace it with OPT_COUNTUP() instead. - Same for OPTION_BOOLEAN; replace it with OPTION_SET_INT and arrange to set 1 to the variable for a true boolean, and otherwise replace it with OPTION_COUNTUP. - Look at each hit in "git grep -e OPT__VERBOSE -e OPT__QUIET" and see if they can be replaced with OPT__VERBOSITY(). I'll follow this message up with a separate patch as an example. Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'Documentation/technical/api-parse-options.txt')
1 files changed, 11 insertions, 5 deletions
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index f6a4a36..acf1760 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -135,9 +135,14 @@ There are some macros to easily define options:
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.
@@ -148,8 +153,9 @@ There are some macros to easily define options:
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.