New API call Xorriso_peek_outlists()

libisoburn/trunk/xorriso/xorriso.h

@@ -628,6 +628,33 @@ int Xorriso_fetch_outlists(struct XorrisO *xorriso, int stack_handle,
                            struct Xorriso_lsT **info_list, int flag);
 
 
+/** Inquire whether messages are pending in redirected result and info channel.
+    This may be used to determine whether a concurrent message watcher already
+    has obtained all pending messages.
+    @since 1.2.6
+    @param xorriso       The environment handle
+    @param stack_handle  An id number returned by Xorriso_push_outlists()
+                         and not yet revoked by Xorriso_pull_outlists().
+                         Submit -1 to address the most recent valid id.
+    @param timeout       Number of seconds after which to return despite
+                         flag bit 2
+    @param flag          Bitfield for control purposes
+                          bit0= fetch result channel
+                          bit1= fetch info channel
+                          bit2= wait and retry until return is 0 or -1
+                         If bit0 and bit1 are 0, both channels get fetched.
+    @return              If > 0:
+                           bit0= messages are pending in outlists
+                           bit1= message watcher is processing fetched messages
+                         Else:
+                          0= no messages are pending anywhere
+                         -1= inappropriate stack_handle
+                         -2= locking failed
+*/
+int Xorriso_peek_outlists(struct XorrisO *xorriso, int stack_handle,
+                          int timeout, int flag);
+
+
 /** Disable the redirection given by stack_handle. If it was the current
     receiver of messages then switch output to the next older redirection
     resp. to the normal channels if no redirections are stacked any more.