Index: uspace/lib/c/include/fibril_synch.h
===================================================================
--- uspace/lib/c/include/fibril_synch.h	(revision d742db216b1d7efda0a82bee848205d7ffe4a730)
+++ uspace/lib/c/include/fibril_synch.h	(revision 1de92fb061a30c6722110b2a588542d6cc5cdb29)
@@ -50,5 +50,6 @@
  *         - may not use any other synchronization primitive,
  *           save for another `fibril_rmutex_t`. This includes nonblocking
- *           operations like cvar signal and mutex unlock.
+ *           operations like cvar signal and mutex unlock, unless otherwise
+ *           specified.
  *         - may not read IPC messages
  *         - may not start a new thread/fibril
@@ -245,4 +246,11 @@
 extern void fibril_semaphore_close(fibril_semaphore_t *);
 
+typedef struct mpsc mpsc_t;
+extern mpsc_t *mpsc_create(size_t);
+extern void mpsc_destroy(mpsc_t *);
+extern errno_t mpsc_send(mpsc_t *, const void *);
+extern errno_t mpsc_receive(mpsc_t *, void *, const struct timeval *);
+extern void mpsc_close(mpsc_t *);
+
 #endif