int unmount_flags,
wimlib_progress_func_t progress_func);
-/** XXX */
+/**
+ * Update a WIM image by adding, deleting, and/or renaming files or directories.
+ *
+ * @param wim
+ * Pointer to the ::WIMStruct for the WIM file to update.
+ * @param image
+ * The 1-based index of the image in the WIM to update. It cannot be
+ * ::WIMLIB_ALL_IMAGES.
+ * @param cmds
+ * An array of ::wimlib_update_command's that specify the update operations
+ * to perform.
+ * @param num_cmds
+ * Number of commands in @a cmds.
+ * @param update_flags
+ * Reserved; must be 0.
+ * @param progress_func
+ * If non-NULL, a function that will be called periodically with the
+ * progress of the current operation.
+ *
+ * @return 0 on success; nonzero on error. There are many possible error codes
+ * (TODO: document them.)
+ */
extern int
wimlib_update_image(WIMStruct *wim,
int image,