1 files changed, 19 insertions, 0 deletions
diff --git a/src/Fl_add_idle.cxx b/src/Fl_add_idle.cxx
index 1afc4e987..6d5e4b038 100644
--- a/src/Fl_add_idle.cxx
+++ b/src/Fl_add_idle.cxx
@@ -49,6 +49,23 @@ static void call_idle() {
   p->cb(p->data); // this may call add_idle() or remove_idle()!
 }
 
+/**
+    Adds a callback function that is called every time by
+    Fl::wait() and also makes it act as though the timeout is
+    zero (this makes Fl::wait() return immediately, so if it is
+    in a loop it is called repeatedly, and thus the idle fucntion is
+    called repeatedly).  The idle function can be used to get background
+    processing done.
+    
+    <P>You can have multiple idle callbacks. To remove an idle callback use Fl::remove_idle().
+    
+    <P>Fl::wait() and Fl::check() call idle callbacks,
+    but Fl::ready() does not.
+    
+    <P>The idle callback can call any FLTK functions, including
+    Fl::wait(), Fl::check(), and Fl::ready().
+    FLTK will not recursively call the idle callback.
+*/
 void Fl::add_idle(void (*cb)(void*), void* data) {
   idle_cb* p = freelist;
   if (p) freelist = p->next;
@@ -66,6 +83,7 @@ void Fl::add_idle(void (*cb)(void*), void* data) {
   }
 }
 
+/** Returns true if the specified idle callback is currently installed. */
 int Fl::has_idle(void (*cb)(void*), void* data) {
   idle_cb* p = first;
   if (!p) return 0;
@@ -75,6 +93,7 @@ int Fl::has_idle(void (*cb)(void*), void* data) {
   }
 }
 
+/** Removes the specified idle callback, if it is installed. */
 void Fl::remove_idle(void (*cb)(void*), void* data) {
   idle_cb* p = first;
   if (!p) return;