diff --git a/src/future/http/HTTPFuture.php b/src/future/http/HTTPFuture.php
--- a/src/future/http/HTTPFuture.php
+++ b/src/future/http/HTTPFuture.php
@@ -179,7 +179,7 @@
       return null;
     }
 
-    $ok = stream_set_blocking($socket, 0);
+    $ok = stream_set_blocking($socket, false);
     if (!$ok) {
       throw new Exception(pht('Failed to set stream nonblocking.'));
     }
diff --git a/src/hgdaemon/ArcanistHgProxyServer.php b/src/hgdaemon/ArcanistHgProxyServer.php
--- a/src/hgdaemon/ArcanistHgProxyServer.php
+++ b/src/hgdaemon/ArcanistHgProxyServer.php
@@ -355,7 +355,7 @@
           $errstr));
     }
 
-    $ok = stream_set_blocking($socket, 0);
+    $ok = stream_set_blocking($socket, false);
     if ($ok === false) {
       throw new Exception(pht('Unable to set socket nonblocking!'));
     }