+struct argpar_iter *argpar_iter_create(unsigned int argc,
+ const char * const *argv,
+ const struct argpar_opt_descr *descrs);
+
+/*
+ * Destroys `iter`, as returned by argpar_iter_create().
+ */
+ARGPAR_HIDDEN
+void argpar_iter_destroy(struct argpar_iter *iter);
+
+/*
+ * Return type of argpar_iter_next().
+ */
+enum argpar_iter_next_status {
+ ARGPAR_ITER_NEXT_STATUS_OK,
+ ARGPAR_ITER_NEXT_STATUS_END,
+ ARGPAR_ITER_NEXT_STATUS_ERROR_UNKNOWN_OPT,
+ ARGPAR_ITER_NEXT_STATUS_ERROR_MISSING_OPT_ARG,
+ ARGPAR_ITER_NEXT_STATUS_ERROR_INVALID_ARG,
+ ARGPAR_ITER_NEXT_STATUS_ERROR_UNEXPECTED_OPT_ARG,
+ ARGPAR_ITER_NEXT_STATUS_ERROR_MEMORY,
+};
+
+/*
+ * Parses and returns the next item from `iter`.
+ *
+ * On success, this function:
+ *
+ * * Sets `*item` to a parsing item which describes the next option
+ * or non-option argument.
+ *
+ * Destroy `*item` with argpar_item_destroy().
+ *
+ * * Returns `ARGPAR_ITER_NEXT_STATUS_OK`.
+ *
+ * If there are no more items to return, this function returns
+ * `ARGPAR_ITER_NEXT_STATUS_END`.
+ *
+ * On failure, this function:
+ *
+ * * Returns one of:
+ *
+ * `ARGPAR_ITER_NEXT_STATUS_ERROR_UNKNOWN_OPT`:
+ * Unknown option (not found in `descrs` as passed to
+ * argpar_iter_create() to create `iter`).
+ *
+ * `ARGPAR_ITER_NEXT_STATUS_ERROR_MISSING_OPT_ARG`:
+ * Missing option argument.
+ *
+ * `ARGPAR_ITER_NEXT_STATUS_ERROR_INVALID_ARG`:
+ * Invalid argument.
+ *
+ * `ARGPAR_ITER_NEXT_STATUS_ERROR_UNEXPECTED_OPT_ARG`:
+ * Unexpected option argument.
+ *
+ * `ARGPAR_ITER_NEXT_STATUS_ERROR_MEMORY`:
+ * Memory error.
+ *
+ * * Except for the `ARGPAR_ITER_NEXT_STATUS_ERROR_MEMORY` status,
+ * sets `*error`, if not `NULL`, to a descriptive error string.
+ * Free `*error` with free().
+ */
+enum argpar_iter_next_status argpar_iter_next(
+ struct argpar_iter *iter, const struct argpar_item **item,
+ char **error);
+
+/*
+ * Returns the number of ingested elements from `argv`, as passed to
+ * argpar_iter_create() to create `*iter`, that were required to produce
+ * the previously returned items.
+ */
+ARGPAR_HIDDEN
+unsigned int argpar_iter_get_ingested_orig_args(const struct argpar_iter *iter);
+
+/*
+ * Destroys `item`, as created by argpar_iter_next().
+ */
+ARGPAR_HIDDEN
+void argpar_item_destroy(const struct argpar_item *item);
+
+/*
+ * Destroys `_item` (`const struct argpar_item *`) and sets it to
+ * `NULL`.
+ */
+#define ARGPAR_ITEM_DESTROY_AND_RESET(_item) \
+ { \
+ argpar_item_destroy(_item); \
+ _item = NULL; \
+ }