X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/1f3ce240ea5d0cc659c45cc8c0457dd10f36d847..699517afce8942f7f43952adfe242d7a0c09f2d0:/lib/eclient.h

diff --git a/lib/eclient.h b/lib/eclient.h
index 1b79cc0..56ff9e6 100644
--- a/lib/eclient.h
+++ b/lib/eclient.h
@@ -144,26 +144,57 @@ 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. */
 
-typedef void disorder_eclient_no_response(void *v);
-/* completion callback with no data */
+/** @brief Trivial completion callback
+ * @param v User data
+ * @param error Error string or NULL on succes
+ */
+typedef void disorder_eclient_no_response(void *v,
+                                          const char *error);
 
 /** @brief String result completion callback
  * @param v User data
- * @param value or NULL
+ * @param error Error string or NULL on succes
+ * @param value Result or NULL
  *
- * @p value can be NULL for disorder_eclient_get(),
- * disorder_eclient_get_global() and disorder_eclient_userinfo().
+ * @p error will be NULL on success.  In this case @p value will be the result
+ * (which might be NULL for disorder_eclient_get(),
+ * disorder_eclient_get_global() and disorder_eclient_userinfo()).
+ *
+ * @p error will be non-NULL on failure.  In this case @p value is always NULL.
  */
-typedef void disorder_eclient_string_response(void *v, const char *value);
-
-typedef void disorder_eclient_integer_response(void *v, long value);
-/* completion callback with a integer result */
+typedef void disorder_eclient_string_response(void *v,
+                                              const char *error,
+                                              const char *value);
 
-typedef void disorder_eclient_volume_response(void *v, int l, int r);
-/* completion callback with a pair of integer results */
+/** @brief String result completion callback
+ * @param v User data
+ * @param error Error string or NULL on succes
+ * @param value Result or 0
+ *
+ * @p error will be NULL on success.  In this case @p value will be the result.
+ *
+ * @p error will be non-NULL on failure.  In this case @p value is always 0.
+ */
+typedef void disorder_eclient_integer_response(void *v,
+                                               const char *error,
+                                               long value);
+/** @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 */