X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/658c8a359409a339d71910f68452bfaa751734c0..cfa78eaa803d4481efa546b515e408e7aaab3dd9:/lib/eclient.h

diff --git a/lib/eclient.h b/lib/eclient.h
index 1b47dff..86caf75 100644
--- a/lib/eclient.h
+++ b/lib/eclient.h
@@ -144,8 +144,7 @@ struct kvp;
 struct sink;
 
 /* Completion callbacks.  These provide the result of operations to the caller.
- * It is always allowed for these to be null pointers if you don't care about
- * the result. */
+ * Unlike in earlier releases, these are not allowed to be NULL. */
 
 /** @brief Trivial completion callback
  * @param v User data
@@ -181,16 +180,53 @@ typedef void disorder_eclient_string_response(void *v,
 typedef void disorder_eclient_integer_response(void *v,
                                                const char *error,
                                                long value);
-/* completion callback with a integer result */
-
-typedef void disorder_eclient_volume_response(void *v, int l, int r);
-/* completion callback with a pair of integer results */
+/** @brief Volume completion callback
+ * @param v User data
+ * @param error Error string or NULL on success
+ * @param l Left channel volume
+ * @param r Right channel volume
+ *
+ * @p error will be NULL on success.  In this case @p l and @p r will be the
+ * result.
+ *
+ * @p error will be non-NULL on failure.  In this case @p l and @p r are always
+ * 0.
+ */
+typedef void disorder_eclient_volume_response(void *v,
+                                              const char *error,
+                                              int l, int r);
 
-typedef void disorder_eclient_queue_response(void *v, struct queue_entry *q);
-/* completion callback for queue/recent listing */
+/** @brief Queue request completion callback
+ * @param v User data
+ * @param error Error string or NULL on success
+ * @param q Head of queue data list
+ *
+ * @p error will be NULL on success.  In this case @p q will be the (head of
+ * the) result.
+ *
+ * @p error will be non-NULL on failure.  In this case @p q may be NULL but
+ * MIGHT also be some subset of the queue.  For consistent behavior it should
+ * be ignored in the error case.
+ */
+typedef void disorder_eclient_queue_response(void *v,
+                                             const char *error,
+                                             struct queue_entry *q);
 
-typedef void disorder_eclient_list_response(void *v, int nvec, char **vec);
-/* completion callback for file listing etc */
+/** @brief List request completion callback
+ * @param v User data
+ * @param error Error string or NULL on success
+ * @param nvec Number of elements in response list
+ * @param vec Pointer to response list
+ *
+ * @p error will be NULL on success.  In this case @p nvec and @p vec will give
+ * the result.
+ *
+ * @p error will be non-NULL on failure.  In this case @p nvec and @p vec will
+ * be 0 and NULL.
+ */
+typedef void disorder_eclient_list_response(void *v,
+                                            const char *error,
+                                            int nvec, char **vec);
 
 disorder_eclient *disorder_eclient_new(const disorder_eclient_callbacks *cb,
                                        void *u);