* UCW Library -- Parsing of command line options
*
* (c) 2013 Jan Moskyto Matejka <mq@ucw.cz>
+ * (c) 2014 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#include <stdlib.h>
#include <stdio.h>
+#ifdef CONFIG_UCW_CLEAN_ABI
+#define cf_def_file ucw_cf_def_file
+#define cf_env_file ucw_cf_env_file
+#define opt_conf_hook_internal ucw_opt_conf_hook_internal
+#define opt_failure ucw_opt_failure
+#define opt_handle_config ucw_opt_handle_config
+#define opt_handle_dumpconfig ucw_opt_handle_dumpconfig
+#define opt_handle_help ucw_opt_handle_help
+#define opt_handle_set ucw_opt_handle_set
+#define opt_help ucw_opt_help
+#define opt_parse ucw_opt_parse
+#endif
+
#define OPT_EXIT_BAD_ARGS 2
/***
- * [[opt]]
+ * [[classes]]
+ * Option classes
+ * --------------
+ *
+ * Each option belongs to one of the following classes, which define
+ * the overall behavior of the option. In most cases, the classes
+ * are set automatically by <<macros,declaration macros>>.
+ *
+ * - `OPT_CL_END`: this is not a real option class, but a signal
+ * that the list of options ends.
+ * - `OPT_CL_BOOL`: a boolean option. If specified without an argument,
+ * it sets the corresponding variable to 1 (true). So does an argument of
+ * `1`, `y`, `yes`, or `true`. Conversely, an argument of `0`, `n`, `no`,
+ * or `false` sets the variable to 0 (false) and the same happens if
+ * the option is given as `--no-`'option' with no argument.
+ * - `OPT_CL_STATIC`: options of this class just take a value and store
+ * it in the variable.
+ * - `OPT_CL_SWITCH`: a multiple-choice switch, which sets the variable
+ * to a fixed value provided in option definition.
+ * - `OPT_CL_INC`: increments the variable (or decrements, if the
+ * `OPT_NEGATIVE` flag is set).
+ * - `OPT_CL_CALL`: instead of setting a variable, call a function
+ * and pass the value of the option to it.
+ * - `OPT_CL_USER`: like `OPT_CL_STATIC`, but with user-defined value
+ * syntax, specified as <<conf:struct_cf_user_type,`cf_user_type`>>.
+ * - `OPT_CL_SECTION`: not a real option, but an instruction to insert
+ * contents of another list of options.
+ * - `OPT_CL_HELP`: no option, just print a help text.
+ * - `OPT_CL_HOOK`: no option, but a definition of a hook. (FIXME)
***/
enum opt_class {
- OPT_CL_END, // end of list
- OPT_CL_BOOL, // boolean value
- OPT_CL_STATIC, // static value
- OPT_CL_SWITCH, // lookup/switch
- OPT_CL_INC, // incremental value
- OPT_CL_CALL, // call a function
- OPT_CL_USER, // user defined value
- OPT_CL_SECTION, // subsection
- OPT_CL_HELP, // help line
- OPT_CL_HOOK, // hook
+ OPT_CL_END,
+ OPT_CL_BOOL,
+ OPT_CL_STATIC,
+ OPT_CL_SWITCH,
+ OPT_CL_INC,
+ OPT_CL_CALL,
+ OPT_CL_USER,
+ OPT_CL_SECTION,
+ OPT_CL_HELP,
+ OPT_CL_HOOK,
+};
+
+/***
+ * [[opt_item]]
+ * Option definitions
+ * ------------------
+ *
+ * The list of options is represented by `struct opt_section`, which points to
+ * a sequence of `struct opt_item`s.
+ *
+ * These structures are seldom used directly -- instead, they are produced
+ * by <<macros,declaration macros>>.
+ ***/
+
+/** A section of option list. **/
+struct opt_section {
+ struct opt_item * opt;
};
-struct opt_section;
+/** A definition of a single option item. **/
struct opt_item {
- const char * name; // long-op
- int letter; // short-op
- void * ptr; // where to save
+ const char * name; // long name (NULL if none)
+ int letter; // short name (0 if none)
+ void * ptr; // variable to store the value to
const char * help; // description in --help
union opt_union {
- struct opt_section * section; // subsection for OPT_SECTION
- int value; // value for OPT_SWITCH
- void (* call)(struct opt_item * opt, const char * value, void * data); // function to call for OPT_CALL
- struct cf_user_type * utype; // specification of the user-defined type
+ struct opt_section * section; // subsection for OPT_CL_SECTION
+ int value; // value for OPT_CL_SWITCH
+ void (* call)(struct opt_item * opt, const char * value, void * data); // function to call for OPT_CL_CALL
+ void (* hook)(struct opt_item * opt, uns event, const char * value, void * data); // function to call for OPT_CL_HOOK
+ struct cf_user_type * utype; // specification of the user-defined type for OPT_CL_USER
} u;
- u16 flags;
+ u16 flags; // as defined below (for hooks, event mask is stored instead)
byte cls; // enum opt_class
byte type; // enum cf_type
};
-struct opt_section {
- struct opt_item * opt;
-};
+/***
+ * [[flags]]
+ * Option flags
+ * ------------
+ *
+ * Each option can specify a combination of the following flags.
+ ***/
+
+#define OPT_REQUIRED 0x1 /** The option must be always present. **/
+#define OPT_REQUIRED_VALUE 0x2 /** The option must have a value. **/
+#define OPT_NO_VALUE 0x4 /** The option must have no value. **/
+#define OPT_MAYBE_VALUE 0x8 /** The option may have a value. **/
+#define OPT_NEGATIVE 0x10 /** Reversing the effect of OPT_INC or saving @false into OPT_BOOL. **/
+#define OPT_NO_HELP 0x20 /** Exclude this option from the help. **/
+#define OPT_LAST_ARG 0x40 /** Stop processing arguments after this line. **/
+#define OPT_SINGLE 0x100 /** The option must appear at most once. **/
+#define OPT_MULTIPLE 0x200 /** The option may appear multiple times; will save all the values into a simple list. **/
+#define OPT_SEEN_AS_LONG 0x400 // Used internally to signal that we currently process the long form of the option
+#define OPT_BEFORE_CONFIG 0x800 /** The option may appear before a config file is loaded. **/
+#define OPT_INTERNAL 0x4000 // Used internally to ask for passing of struct opt_context to OPT_CALL
-#define OPT_ITEMS .opt = ( struct opt_item[] ) /** List of sub-items. **/
+/**
+ * If none of these flags are specified, a default is chosen automatically
+ * according to option class:
+ *
+ * - `OPT_MAYBE_VALUE` for `OPT_CL_STATIC`
+ * - `OPT_NO_VALUE` for `OPT_CL_BOOL`, `OPT_CL_SWITCH` and `OPT_CL_INC`
+ * - An error is reported in all other cases.
+ **/
+#define OPT_VALUE_FLAGS (OPT_REQUIRED_VALUE | OPT_NO_VALUE | OPT_MAYBE_VALUE)
/***
- * Sub-items to be enclosed in OPT_ITEMS { } list
- * ----------------------------------------------
- *
- * OPT_HELP_OPTION declares --help and prints a line about that
- * OPT_HELP prints a line into help
- * OPT_HELP2 prints two strings onto a line using the same tab structure as the option listing
- * OPT_BOOL declares boolean option with an auto-negation (--sth and --no-sth). It's also possible to write --sth=y/yes/true/1/n/no/false/0.
- * OPT_STRING, OPT_UNS, OPT_INT declare simple string/uns/int option
- * OPT_SWITCH declares one choice of a switch statement; these have common target and different `value`s; last wins unless OPT_SINGLE is set;
- * parser fails if it matches an OPT_SWITCH with OPT_SINGLE set and also target set.
- * Target must be of signed integer type; it is set to -1 if no switch appears at the command-line.
- * OPT_CALL calls the given function with an argument, giving also the opt_item structure and some custom data.
- * OPT_HOOK is called at the specified place: before option parsing, before value parsing and after value parsing as specified in @flags;
- * OPT_HOOK_BEFORE_ARG gets @opt and @value set to NULL;
- * OPT_HOOK_BEFORE_VALUE gets both @opt and @value set.
- * OPT_HOOK_AFTER_VALUE gets both @opt and @value set.
- * OPT_USER declares a custom type of value defined by the given @cf_user_type in @ttype
- * OPT_INC declares an incremental value like -v/--verbose
- * OPT_SECTION declares a subsection
+ * [[macros]]
+ * Macros for declaration of options
+ * ---------------------------------
*
+ * In most cases, option definitions are built using these macros.
***/
-#define OPT_HELP_OPTION OPT_CALL(0, "help", opt_show_help_internal, NULL, OPT_NO_VALUE, "Show this help")
+/** Used inside `struct opt_section` to start a list of items. **/
+#define OPT_ITEMS .opt = ( struct opt_item[] )
+
+/** No option, just a piece of help text. **/
#define OPT_HELP(line) { .help = line, .cls = OPT_CL_HELP }
+
+/** Standard `--help` option. **/
+#define OPT_HELP_OPTION OPT_CALL(0, "help", opt_handle_help, NULL, OPT_BEFORE_CONFIG | OPT_INTERNAL | OPT_NO_VALUE, "\tShow this help")
+
+/** Boolean option. @target should be a variable of type `int`. **/
#define OPT_BOOL(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_BOOL, .type = CT_INT }
+
+/** String option. @target should be a variable of type `char *`. **/
#define OPT_STRING(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_STATIC, .type = CT_STRING }
-#define OPT_U64(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_STATIC, .type = CT_U64 }
+
+// FIXME: Check that the target is of the right type (likewise in other statically typed options)
+/** Ordinary integer option. @target should be a variable of type `int`. **/
#define OPT_INT(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_STATIC, .type = CT_INT }
+
+/** 64-bit integer option. @target should be a variable of type `u64`. **/
+#define OPT_U64(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_STATIC, .type = CT_U64 }
+
+/** Floating-point option. @target should be a variable of type `double`. **/
#define OPT_DOUBLE(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_STATIC, .type = CT_DOUBLE }
+
+/** IP address option, currently IPv4 only. @target should be a variable of type `u32`. **/
#define OPT_IP(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_STATIC, .type = CT_IP }
+
+/** Switch option. @target should be a variable of type `int` and it will be set to the value @val. **/
#define OPT_SWITCH(shortopt, longopt, target, val, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .help = desc, .flags = fl, .cls = OPT_CL_SWITCH, .type = CT_LOOKUP, .u.value = val }
-#define OPT_CALL(shortopt, longopt, fn, data, fl, desc) { .letter = shortopt, .name = longopt, .ptr = data, .help = desc, .u.call = fn, .flags = fl, .cls = OPT_CL_CALL, .type = CT_USER }
-#define OPT_USER(shortopt, longopt, target, ttype, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .u.utype = &ttype, .flags = fl, .help = desc, .cls = OPT_CL_USER, .type = CT_USER }
+
+/** Incrementing option. @target should be a variable of type `int`. **/
#define OPT_INC(shortopt, longopt, target, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .flags = fl, .help = desc, .cls = OPT_CL_INC, .type = CT_INT }
-#define OPT_SECTION(sec) { .cls = OPT_CL_SECTION, .u.section = &sec }
-#define OPT_HOOK(fn, data, fl) { .cls = OPT_CL_HOOK, .u.call = fn, .flags = OPT_NO_HELP | fl, .ptr = data }
-#define OPT_END { .cls = OPT_CL_END }
-/***
- * UCW Conf options
- * ~~~~~~~~~~~~~~~~
- *
- * OPT_CONF_OPTIONS declares -C and -S as described in @getopt.h
- ***/
+/**
+ * When this option appears, call the function @fn with parameters @item, @value, @data,
+ * where @item points to the <<struct_opt_item,`struct opt_item`>> of this option,
+ * @value contains the current argument of the option (NULL if there is none),
+ * and @data is specified here.
+ **/
+#define OPT_CALL(shortopt, longopt, fn, data, fl, desc) { .letter = shortopt, .name = longopt, .ptr = data, .help = desc, .u.call = fn, .flags = fl, .cls = OPT_CL_CALL, .type = CT_USER }
-#ifdef CONFIG_UCW_DEBUG
-#define OPT_CONF_OPTIONS OPT_CONF_CONFIG, OPT_CONF_SET, OPT_CONF_DUMPCONFIG, OPT_CONF_HOOK
-#else
-#define OPT_CONF_OPTIONS OPT_CONF_CONFIG, OPT_CONF_SET, OPT_CONF_HOOK
-#endif
+/**
+ * An option with user-defined syntax. @ttype is a <<conf:struct_cf_user_type,`cf_user_type`>>
+ * describing the syntax, @target is a variable of the corresponding type.
+ **/
+#define OPT_USER(shortopt, longopt, target, ttype, fl, desc) { .letter = shortopt, .name = longopt, .ptr = &target, .u.utype = &ttype, .flags = fl, .help = desc, .cls = OPT_CL_USER, .type = CT_USER }
-#define OPT_CONF_CONFIG OPT_CALL('C', "config", opt_conf_internal, NULL, OPT_REQUIRED_VALUE, "Override the default configuration file")
-#define OPT_CONF_SET OPT_CALL('S', "set", opt_conf_internal, NULL, OPT_REQUIRED_VALUE, "Manual setting of a configuration item")
-#define OPT_CONF_DUMPCONFIG OPT_CALL(0, "dumpconfig", opt_conf_internal, NULL, OPT_NO_VALUE, "Dump program configuration")
-#define OPT_CONF_HOOK OPT_HOOK(opt_conf_hook_internal, NULL, OPT_HOOK_BEFORE_VALUE)
+/** A sub-section. **/
+#define OPT_SECTION(sec) { .cls = OPT_CL_SECTION, .u.section = &sec }
-void opt_conf_internal(struct opt_item * opt, const char * value, void * data);
-void opt_conf_hook_internal(struct opt_item * opt, const char * value, void * data);
+/** Declares a <<hooks,hook>> to call upon any event from the specified set. **/
+#define OPT_HOOK(fn, data, events) { .cls = OPT_CL_HOOK, .u.hook = fn, .flags = events, .ptr = data }
-extern int opt_parsed_count; /** How many opts have been already parsed. **/
-extern int opt_conf_parsed_count;
+/** A terminator signalling the end of the option list. **/
+#define OPT_END { .cls = OPT_CL_END }
/***
- * Predefined shortopt arguments
- * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- *
- * for the preceeding calls if positional args wanted.
- * Arguments are processed in the order of the numbers given to them. There must be first
- * the args with OPT_REQUIRED (see lower) and after them the args without OPT_REQUIRED, no mixing.
- * You may define a catch-all option as OPT_POSITIONAL_TAIL. After this, no positional arg is allowed.
- * You may shuffle the positional arguments in any way in the opt sections but the numbering must obey
- * the rules given here.
+ * [[positional]]
+ * Positional arguments
+ * --------------------
+ *
+ * In addition to short and long options, the parser can also process 'positional
+ * arguments', which don't start with a dash and whose meaning depends solely on
+ * their position.
+ *
+ * Positional arguments are declared as options with short name `OPT_POSITIONAL(n)`
+ * (where `n` is the position of the argument, starting with 1) and long name
+ * NULL. To accept an arbitrary number of positional arguments, use
+ * `OPT_POSITIONAL_TAIL` instead, which matches all arguments, for which no
+ * `OPT_POSITIONAL` is defined. (In the latter case, you probably want to define
+ * the argument as `OPT_MULTIPLE` or `OPT_CALL`, so that the values do not
+ * overwrite each other.)
+ *
+ * Options and positional arguments can be mixed arbitrarily. When a `--` appears
+ * as an argument, it is understood as a signal that all other arguments are
+ * positional.
+ *
+ * `OPT_REQUIRED` can be used with positional arguments, but all required arguments
+ * must come before the non-required ones. When `OPT_POSITIONAL_TAIL` is declared
+ * required, it means that it must match at least once.
+ *
+ * Ordering of positional arguments within the list of options need not match
+ * their positions. Holes in position numbering are inadvisable.
***/
-#define OPT_POSITIONAL(n) (OPT_POSITIONAL_TAIL+(n))
-#define OPT_POSITIONAL_TAIL 256
-
+#define OPT_POSITIONAL(n) (OPT_POSITIONAL_TAIL+(n))
+#define OPT_POSITIONAL_TAIL 128
/***
- * Flags for the preceeding calls
- * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * [[func]]
+ * Functions
+ * ---------
***/
-#define OPT_REQUIRED 0x1 /** Argument must appear at the command line **/
-#define OPT_REQUIRED_VALUE 0x2 /** Argument must have a value **/
-#define OPT_NO_VALUE 0x4 /** Argument must have no value **/
-#define OPT_MAYBE_VALUE 0x8 /** Argument may have a value **/
-#define OPT_VALUE_FLAGS (OPT_REQUIRED_VALUE | OPT_NO_VALUE | OPT_MAYBE_VALUE)
-#define OPT_NEGATIVE 0x10 /** Reversing the effect of OPT_INC or saving @false into OPT_BOOL **/
-#define OPT_NO_HELP 0x20 /** Omit this line from help **/
-#define OPT_LAST_ARG 0x40 /** Stop processing argv after this line **/
-#define OPT_SINGLE 0x100 /** Argument must appear at most once **/
-#define OPT_MULTIPLE 0x200 /** Argument may appear any time; will save all the values into a simple list **/
-#define OPT_HOOK_BEFORE_ARG 0x1000 /** Call before option parsing **/
-#define OPT_HOOK_BEFORE_VALUE 0x2000 /** Call before value parsing **/
-#define OPT_HOOK_AFTER_VALUE 0x4000 /** Call after value parsing **/
+/**
+ * Parse all arguments, given in a NULL-terminated array of strings.
+ *
+ * Typically, this is called from `main(argc, argv)` as `opt_parse(options, argv+1)`,
+ * skipping the 0th argument, which contains program name.
+ *
+ * Returns the number of arguments used (which need not be all of them
+ * if `OPT_LAST_ARG` was encountered).
+ *
+ * The argument array is left untouched.
+ * However, option values are not necessarily copied, the variables
+ * set by the parser may point to the argument array.
+ **/
+int opt_parse(const struct opt_section * options, char ** argv);
+
+/**
+ * Report parsing failure, suggest `--help`, and abort the program with
+ * exit code 2.
+ **/
+void opt_failure(const char * mesg, ...) FORMAT_CHECK(printf,1,2) NONRET;
+void opt_help(const struct opt_section * sec);
+void opt_handle_help(struct opt_item * opt, const char * value, void * data);
/***
- * Value flags defaults
- * ~~~~~~~~~~~~~~~~~~~~
+ * [[conf]]
+ * Cooperating with config file parser
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * Parsing of command-line options and configuration files are usually
+ * intertwined in a somewhat tricky way. We want to provide command-line
+ * options that control the name of the configuration file, or possibly to
+ * override configuration settings from the command line. On the other hand,
+ * regular command-line options can refer to values loaded from the
+ * program's configuration.
*
- * OPT_NO_VALUE for OPT_BOOL, OPT_SWITCH and OPT_INC
- * OPT_MAYBE_VALUE for OPT_STRING, OPT_UNS, OPT_INT
- * Some of the value flags (OPT_NO_VALUE, OPT_MAYBE_VALUE, OPT_REQUIRED_VALUE)
- * must be specified for OPT_CALL and OPT_USER.
+ * To achieve this goal, the option parser is able to cooperate with the
+ * config file parser. This is enabled by listing the `OPT_CONF_OPTIONS`
+ * macro in the list of command-line options.
+ *
+ * The following options are defined for you:
+ *
+ * - `-C` (`--config`) to load a specific configuration file. This option
+ * suppresses loading of the default configuration, but it can be given
+ * multiple times to merge settings from several files.
+ *
+ * - `-S` (`--set`) to include a part of configuration inline. For example,
+ * you can use `-Ssection.item=value` to change a single configuration item.
+ *
+ * - `--dumpconfig` to dump the configuration to standard output and exit.
+ * (This is available only if the program is compiled with `CONFIG_UCW_DEBUG`.)
+ *
+ * The default configuration file (as specified by <<var_cf_def_file,`cf_def_file`>>) is loaded
+ * as soon as the first option different from `-C` is encountered, unless
+ * a different file has been already loaded. For this reason, `-C` must be
+ * the very first argument given to the program.
+ *
+ * This interface supersedes <<conf:getopt_h,`cf_getopt()`>>.
***/
-static uns opt_default_value_flags[] = {
- [OPT_CL_BOOL] = OPT_NO_VALUE,
- [OPT_CL_STATIC] = OPT_MAYBE_VALUE,
- [OPT_CL_SWITCH] = OPT_NO_VALUE,
- [OPT_CL_INC] = OPT_NO_VALUE,
- [OPT_CL_CALL] = 0,
- [OPT_CL_USER] = 0,
- [OPT_CL_SECTION] = 0,
- [OPT_CL_HELP] = 0
-};
-
-extern const struct opt_section * opt_section_root;
-void opt_help_internal(const struct opt_section * help);
-
-static void opt_help(void) {
- opt_help_internal(opt_section_root);
-}
+#ifdef CONFIG_UCW_DEBUG
+#define OPT_CONF_OPTIONS OPT_CONF_CONFIG, OPT_CONF_SET, OPT_CONF_DUMPCONFIG, OPT_CONF_HOOK
+#else
+#define OPT_CONF_OPTIONS OPT_CONF_CONFIG, OPT_CONF_SET, OPT_CONF_HOOK
+#endif
-static void opt_usage(void) {
- fprintf(stderr, "Run with argument --help for more information.\n");
-}
+#define OPT_CONF_CONFIG OPT_CALL('C', "config", opt_handle_config, NULL, OPT_BEFORE_CONFIG | OPT_INTERNAL | OPT_REQUIRED_VALUE, "<file>\tOverride the default configuration file")
+#define OPT_CONF_SET OPT_CALL('S', "set", opt_handle_set, NULL, OPT_BEFORE_CONFIG | OPT_INTERNAL | OPT_REQUIRED_VALUE, "<item>\tManual setting of a configuration item")
+#define OPT_CONF_DUMPCONFIG OPT_CALL(0, "dumpconfig", opt_handle_dumpconfig, NULL, OPT_INTERNAL | OPT_NO_VALUE, "\tDump program configuration")
+#define OPT_CONF_HOOK OPT_HOOK(opt_conf_hook_internal, NULL, OPT_HOOK_BEFORE_VALUE | OPT_HOOK_FINAL | OPT_HOOK_INTERNAL)
-static void opt_show_help_internal(struct opt_item * opt UNUSED, const char * value UNUSED, void * data UNUSED) {
- opt_help();
- exit(0);
-}
+void opt_handle_config(struct opt_item * opt, const char * value, void * data);
+void opt_handle_set(struct opt_item * opt, const char * value, void * data);
+void opt_handle_dumpconfig(struct opt_item * opt, const char * value, void * data);
+void opt_conf_hook_internal(struct opt_item * opt, uns event, const char * value, void * data);
+// XXX: This is duplicated with <ucw/getopt.h>, but that one will hopefully go away one day.
+/**
+ * The name of the default configuration file (NULL if configuration has been
+ * already loaded). It is initialized to `CONFIG_UCW_DEFAULT_CONFIG`, but you
+ * usually want to replace it by your own config file.
+ */
+extern char *cf_def_file;
/**
- * Parse all the arguments. Run the @callback for each of the positional argument.
+ * Name of environment variable that can override what configuration is loaded.
+ * Defaults to the value of the `CONFIG_UCW_ENV_VAR_CONFIG` compile-time option.
**/
-void opt_parse(const struct opt_section * options, char ** argv);
+extern char *cf_env_file;
+
+/***
+ * [[hooks]]
+ * Hooks
+ * -----
+ *
+ * You can supply hook functions, which will be called by the parser upon various
+ * events. Hooks are declared as option items of class `OPT_CL_HOOK`, whose @flags
+ * field specifies a mask of events the hook wants to receive.
+ *
+ * Please note that the hook interface is not considered stable yet,
+ * so it might change in future versions of libucw.
+ *
+ * The following events are defined:
+ ***/
+
+#define OPT_HOOK_BEFORE_ARG 0x1 /** Call before option parsing **/
+#define OPT_HOOK_BEFORE_VALUE 0x2 /** Call before value parsing **/
+#define OPT_HOOK_AFTER_VALUE 0x4 /** Call after value parsing **/
+#define OPT_HOOK_FINAL 0x8 /** Call just before opt_parse() returns **/
+#define OPT_HOOK_INTERNAL 0x4000 // Used internally to ask for passing of struct opt_context
#endif