-void parse_options(int argc, char **argv, const OptionDef *options,
- void (* parse_arg_function)(const char*));
+void parse_options(void *optctx, int argc, char **argv, const OptionDef *options,
+ void (* parse_arg_function)(void *optctx, const char*));
+
+/**
+ * Parse one given option.
+ *
+ * @return on success 1 if arg was consumed, 0 otherwise; negative number on error
+ */
+int parse_option(void *optctx, const char *opt, const char *arg, const OptionDef *options);
+
+/**
+ * Find the '-loglevel' option in the commandline args and apply it.
+ */
+void parse_loglevel(int argc, char **argv, const OptionDef *options);