Index: uspace/lib/c/include/ipc/logger.h
===================================================================
--- uspace/lib/c/include/ipc/logger.h	(revision 1f2dd20bb7535f5d8a3876582e186cb29b7d6453)
+++ uspace/lib/c/include/ipc/logger.h	(revision 76d92db112f9f96e53f73ce4e71c158bbd030916)
@@ -38,5 +38,6 @@
 typedef enum {
 	LOGGER_REGISTER = IPC_FIRST_USER_METHOD,
-	LOGGER_MESSAGE
+	LOGGER_MESSAGE,
+	LOGGER_BLOCK_UNTIL_READER_CHANGED
 } logger_sink_request_t;