+/**
+ * Create hash table from colon separated key-value pairs input text.
+ *
+ * Accepts input text as it was specified by users. Splits the colon
+ * separated key-value pairs and creates a hash table from these items.
+ * Optionally supports special forms which are useful for different CLI
+ * features.
+ *
+ * Typical form: <key>=<val>[:<key>=<val>]*
+ * Generic list of key-value pairs, all items being equal. Mere set.
+ *
+ * ID form: <id>[:<key>=<val>]*
+ * First item is not a key-value pair, instead it's an identifier. Used
+ * to specify a protocol decoder, or a device driver, or an input/output
+ * file format, optionally followed by more parameters' values. The ID
+ * part of the input spec is not optional.
+ *
+ * Optional ID: [<sel>=<id>][:<key>=<val>]*
+ * All items are key-value pairs. The first item _may_ be an identifier,
+ * if its key matches a caller specified key name. Otherwise the input
+ * text is the above typical form, a mere list of key-value pairs while
+ * none of them is special.
+ *
+ * @param[in] arg Input text.
+ * @param[in] sep_first Boolean, whether ID form is required.
+ * @param[in] key_first Keyword name if optional ID is applicable.
+ *
+ * @returns A hash table which contains the key/value pairs, or #NULL
+ * when the input is invalid.
+ */
+GHashTable *parse_generic_arg(const char *arg,
+ gboolean sep_first, const char *key_first)