1 files changed, 6 insertions, 1 deletions

diff --git a/src/lanes.lua b/src/lanes.lua
index 49900f9..fd3d22b 100644
--- a/src/lanes.lua
+++ b/src/lanes.lua
@@ -73,6 +73,7 @@ lanes.configure = function( settings_)
         keepers_gc_threshold = -1,
         on_state_create = nil,
         shutdown_timeout = 0.25,
+        shutdown_mode = "hard",
         with_timers = true,
         track_lanes = false,
         demote_full_userdata = nil,
@@ -113,6 +114,11 @@ lanes.configure = function( settings_)
             -- shutdown_timeout should be a number >= 0
             return type( val_) == "number" and val_ >= 0
         end,
+        shutdown_mode = function( val_)
+            local valid_hooks = { soft = true, hard = true, call = true, ret = true, line = true, count = true }
+            -- shutdown_mode should be a known hook mask
+            return valid_hooks[val_]
+        end,
         track_lanes = boolean_param_checker,
         demote_full_userdata = boolean_param_checker,
         verbose_errors = boolean_param_checker
@@ -367,7 +373,6 @@ lanes.configure = function( settings_)
 
 
     if settings.with_timers ~= false then
-
         --
         -- On first 'require "lanes"', a timer lane is spawned that will maintain
         -- timer tables and sleep in between the timer events. All interaction with