1 files changed, 11 insertions, 3 deletions
diff --git a/include/term/term.h b/include/term/term.h
index dc41114..d413db5 100644
--- a/include/term/term.h
+++ b/include/term/term.h
@@ -408,11 +408,16 @@ struct term_view {
     const uint32_t *palette;    /* TERM_PALETTE_SIZE ARGB entries */
 };
 
+/* The view of s, NULL for a NULL s. The view and view->palette keep their
+ * address until term_snapshot_free(); their contents change on each update. */
 TERM_API const struct term_view *term_snapshot_view(const struct term_snapshot *s);
-/* The cells of viewport row y: view->size.x entries. */
+/* The cells of viewport row y: view->size.x entries. NULL when y is outside
+ * the viewport or s is NULL. An update can move the cells, so the pointer is
+ * valid only until the next term_snapshot_update() or term_snapshot_free() of s. */
 TERM_API const struct term_cell *term_snapshot_row(const struct term_snapshot *s, int y);
 /* An identity for the content of row y. Two rows with the same key hold the
- * same cells, also when the content moved to another row. */
+ * same cells, also when the content moved to another row. 0 when y is outside
+ * the viewport or s is NULL. */
 TERM_API uint64_t term_snapshot_row_key(const struct term_snapshot *s, int y);
 
 /* Number of rows in history above the screen. 0 if alternate screen or no history. */
@@ -423,10 +428,13 @@ TERM_API int term_history_rows(const struct term *t);
  * an empty string; NULL means allocation failed or t is NULL. Release the
  * result with term_text_free(). */
 TERM_API char *term_history_text(struct term *t, int max_rows);
+/* The selected columns of viewport row y, end exclusive. An empty span when y
+ * is outside the viewport or s is NULL. */
 TERM_API struct term_span term_snapshot_row_selection(const struct term_snapshot *s, int y);
 
 /* The code points of a cluster cell. Returns the number of code points and
- * writes at most cap of them. */
+ * writes at most cap of them. Writes nothing when cps is NULL or cap is 0.
+ * Returns 0 when s is NULL. */
 TERM_API int term_snapshot_cluster(const struct term_snapshot *s, uint32_t text, uint32_t *cps, int cap);
 
 /* The ARGB value of a color in a view. */