4 files changed, 15 insertions, 0 deletions
diff --git a/src/event/DeferredMonitor.hxx b/src/event/DeferredMonitor.hxx
index d4c812e44..96ad5e282 100644
--- a/src/event/DeferredMonitor.hxx
+++ b/src/event/DeferredMonitor.hxx
@@ -38,6 +38,9 @@ class EventLoop;
 
 /**
  * Defer execution of an event into an #EventLoop.
+ *
+ * This class is thread-safe, however the constructor must be called
+ * from the thread that runs the #EventLoop
  */
 class DeferredMonitor
 #ifdef USE_INTERNAL_EVENTLOOP
diff --git a/src/event/IdleMonitor.hxx b/src/event/IdleMonitor.hxx
index b040915e7..6f7365532 100644
--- a/src/event/IdleMonitor.hxx
+++ b/src/event/IdleMonitor.hxx
@@ -32,6 +32,10 @@ class EventLoop;
  * An event that runs when the EventLoop has become idle, before
  * waiting for more events.  This class is not thread-safe; all
  * methods must be run from EventLoop's thread.
+ *
+ * This class is not thread-safe, all methods must be called from the
+ * thread that runs the #EventLoop, except where explicitly documented
+ * as thread-safe.
  */
 class IdleMonitor {
 #ifdef USE_INTERNAL_EVENTLOOP
diff --git a/src/event/SocketMonitor.hxx b/src/event/SocketMonitor.hxx
index f6aac2bd6..768f21c57 100644
--- a/src/event/SocketMonitor.hxx
+++ b/src/event/SocketMonitor.hxx
@@ -50,6 +50,10 @@ class EventLoop;
  * you're interested in, or Cancel() to cancel your subscription.  The
  * #EventLoop will invoke virtual method OnSocketReady() as soon as
  * any of the subscribed events are ready.
+ *
+ * This class is not thread-safe, all methods must be called from the
+ * thread that runs the #EventLoop, except where explicitly documented
+ * as thread-safe.
  */
 class SocketMonitor {
 #ifdef USE_GLIB_EVENTLOOP
diff --git a/src/event/TimeoutMonitor.hxx b/src/event/TimeoutMonitor.hxx
index 568aa27ef..9f6b19bc7 100644
--- a/src/event/TimeoutMonitor.hxx
+++ b/src/event/TimeoutMonitor.hxx
@@ -31,6 +31,10 @@ class EventLoop;
 /**
  * This class monitors a timeout.  Use Schedule() to begin the timeout
  * or Cancel() to cancel it.
+ *
+ * This class is not thread-safe, all methods must be called from the
+ * thread that runs the #EventLoop, except where explicitly documented
+ * as thread-safe.
  */
 class TimeoutMonitor {
 #ifdef USE_INTERNAL_EVENTLOOP