document until-condition

diff --git a/doc/lispref/threads.texi b/doc/lispref/threads.texi
index 760452808cf8485f93ffa08f0423b4c20554e578..8094a68f9aa190fae71b1df68c6e8ac05d00c3ec 100644 (file)
--- a/doc/lispref/threads.texi
+++ b/doc/lispref/threads.texi
@@ -236,3 +236,9 @@ Return the name of @var{cond}, as passed to
 Return the mutex associated with @var{cond}.  Note that the associated
 mutex cannot be changed.
 @end defun
+
+@defmac until-condition test cond
+Acquire the mutex associated with @var{cond}, and then loop, invoking
+the form @var{test}.  If @var{test} evaluates to @code{nil}, invoke
+@code{condition-wait} on @var{cond}.
+@end defmac