output: document wlr_output_export_dmabuf

include/wlr/types/wlr_output.h

@@ -385,6 +385,12 @@ size_t wlr_output_get_gamma_size(struct wlr_output *output);
  */
 void wlr_output_set_gamma(struct wlr_output *output, size_t size,
 	const uint16_t *r, const uint16_t *g, const uint16_t *b);
+/**
+ * Exports the output's current back-buffer as a DMA-BUF (ie. the buffer that
+ * will be displayed on next commit).
+ *
+ * The caller is responsible for cleaning up the DMA-BUF attributes.
+ */
 bool wlr_output_export_dmabuf(struct wlr_output *output,
 	struct wlr_dmabuf_attributes *attribs);
 /**