-int mixer_control(int *left, int *right, int set);
-/* get/set the current level. If @set@ is true then the level is set
- * according to the pointers. In either case the eventual level is
- * returned via the pointers.
- *
- * Returns 0 on success and -1 on error.
- */
+ /** @brief Get the volume
+ * @param left Where to store left-channel volume
+ * @param right Where to store right-channel volume
+ * @return 0 on success, non-0 on error
+ */
+ int (*get)(int *left, int *right);
+
+ /** @brief Set the volume
+ * @param left Pointer to target left-channel volume
+ * @param right Pointer to target right-channel volume
+ * @return 0 on success, non-0 on error
+ *
+ * @p left and @p right are updated with the actual volume set.
+ */
+ int (*set)(int *left, int *right);
+
+ /** @brief Default device */
+ const char *device;
+
+ /** @brief Default channel */
+ const char *channel;
+};
+
+int mixer_control(int api, int *left, int *right, int set);
+const char *mixer_default_device(int api);
+const char *mixer_default_channel(int api);
+int mixer_supported(int api);
+
+extern const struct mixer mixer_oss;
+extern const struct mixer mixer_alsa;