opt: add opt_log_stderr_exit helper, and opt_usage NULL option.

[ccan] / ccan / opt / opt.h

diff --git a/ccan/opt/opt.h b/ccan/opt/opt.h
index 1e25cce370ad19b002587a2d59951ddd0236bd5b..7d7bc571fc2363f40241497297bcdc32ff5f6716 100644 (file)
--- a/ccan/opt/opt.h
+++ b/ccan/opt/opt.h
@@ -48,7 +48,7 @@ struct opt_table {
  *     OPT_WITH_ARG()
  */
 #define OPT_WITHOUT_ARG(names, cb, arg, desc)  \
-       (names), OPT_CB_NOARG((cb), (arg)), (desc)
+       { (names), OPT_CB_NOARG((cb), (arg)), (desc) }
 
 /**
  * OPT_WITH_ARG() - macro for initializing long and short option (with arg)
@@ -83,7 +83,7 @@ struct opt_table {
  *     OPT_WITHOUT_ARG()
  */
 #define OPT_WITH_ARG(name, cb, show, arg, desc)        \
-       (name), OPT_CB_ARG((cb), (show), (arg)), (desc)
+       { (name), OPT_CB_ARG((cb), (show), (arg)), (desc) }
 
 /**
  * OPT_SUBTABLE() - macro for including another table inside a table.
@@ -109,14 +109,15 @@ struct opt_table {
  * The table must be terminated by OPT_ENDTABLE.
  *
  * Example:
+ * static int verbose = 0;
  * static struct opt_table opts[] = {
- *     { OPT_WITHOUT_ARG("--verbose", opt_inc_intval, &verbose),
- *       "Verbose mode (can be specified more than once)" },
- *     { OPT_WITHOUT_ARG("-v", opt_inc_intval, &verbose),
- *       "Verbose mode (can be specified more than once)" },
- *     { OPT_WITHOUT_ARG("--usage", opt_usage_and_exit,
- *                       "args...\nA silly test program."),
- *       "Print this message." },
+ *     OPT_WITHOUT_ARG("--verbose", opt_inc_intval, &verbose,
+ *                     "Verbose mode (can be specified more than once)"),
+ *     OPT_WITHOUT_ARG("-v", opt_inc_intval, &verbose,
+ *                     "Verbose mode (can be specified more than once)"),
+ *     OPT_WITHOUT_ARG("--usage", opt_usage_and_exit,
+ *                     "args...\nA silly test program.",
+ *                     "Print this message."),
  *     OPT_ENDTABLE
  * };
  *
@@ -150,7 +151,7 @@ void opt_register_table(const struct opt_table table[], const char *desc);
  * opt_register_arg - register an option with an arguments
  * @names: the names of the option eg. "--foo", "-f" or "--foo/-f/--foobar".
  * @cb: the callback when the option is found.
- * @show: the callback when the option is found.
+ * @show: the callback to print the value in get_usage (or NULL)
  * @arg: the argument to hand to @cb.
  * @desc: the verbose desction of the option (for opt_usage()), or NULL.
  *
@@ -166,8 +167,12 @@ void opt_register_table(const struct opt_table table[], const char *desc);
  * @cb returns false, opt_parse() will stop parsing and return false.
  *
  * Example:
- *     opt_register_arg("--explode", explode_cb, NULL,
- *                      "Make the machine explode (developers only)");
+ * static char *explode(const char *optarg, void *unused)
+ * {
+ *     errx(1, "BOOM! %s", optarg);
+ * }
+ * ...
+ *     opt_register_arg("--explode/--boom", explode, NULL, NULL, opt_hidden);
  */
 #define opt_register_arg(names, cb, show, arg, desc)                   \
        _opt_register((names), OPT_CB_ARG((cb), (show), (arg)), (desc))
@@ -176,7 +181,7 @@ void opt_register_table(const struct opt_table table[], const char *desc);
  * opt_parse - parse arguments.
  * @argc: pointer to argc
  * @argv: argv array.
- * @errlog: the function to print errors (usually opt_log_stderr).
+ * @errlog: the function to print errors
  *
  * This iterates through the command line and calls callbacks registered with
  * opt_register_table()/opt_register_arg()/opt_register_noarg().  If there
@@ -187,10 +192,13 @@ void opt_register_table(const struct opt_table table[], const char *desc);
  * remain, and true is returned.
  *
  * Example:
- *     if (!opt_parse(argc, argv, opt_log_stderr)) {
- *             printf("%s", opt_usage(argv[0], "<args>..."));
+ *     if (!opt_parse(&argc, argv, opt_log_stderr)) {
+ *             printf("You screwed up, aborting!\n");
  *             exit(1);
  *     }
+ *
+ * See Also:
+ *     opt_log_stderr, opt_log_stderr_exit
  */
 bool opt_parse(int *argc, char *argv[], void (*errlog)(const char *fmt, ...));
 
@@ -198,10 +206,26 @@ bool opt_parse(int *argc, char *argv[], void (*errlog)(const char *fmt, ...));
  * opt_log_stderr - print message to stderr.
  * @fmt: printf-style format.
  *
- * This is the standard helper for opt_parse, to print errors.
+ * This is a helper for opt_parse, to print errors to stderr.
+ *
+ * See Also:
+ *     opt_log_stderr_exit
  */
 void opt_log_stderr(const char *fmt, ...);
 
+/**
+ * opt_log_stderr_exit - print message to stderr, then exit(1)
+ * @fmt: printf-style format.
+ *
+ * Just like opt_log_stderr, only then does exit(1).  This means that
+ * when handed to opt_parse, opt_parse will never return false.
+ *
+ * Example:
+ *     // This never returns false; just exits if there's an erorr.
+ *     opt_parse(&argc, argv, opt_log_stderr_exit);
+ */
+void opt_log_stderr_exit(const char *fmt, ...);
+
 /**
  * opt_invalid_argument - helper to allocate an "Invalid argument '%s'" string
  * @arg: the argument which was invalid.
@@ -219,6 +243,10 @@ char *opt_invalid_argument(const char *arg);
  * and a table of all the options with their descriptions.  If an option has
  * description opt_hidden, it is not shown here.
  *
+ * If "extra" is NULL, then the extra information is taken from any
+ * registered option which calls opt_usage_and_exit().  This avoids duplicating
+ * that string in the common case.
+ *
  * The result should be passed to free().
  */
 char *opt_usage(const char *argv0, const char *extra);