C-Stack test does not assume minimum of 400 slots
diff --git a/testes/cstack.lua b/testes/cstack.lua
index cd74fd2..e3e14f7 100644
--- a/testes/cstack.lua
+++ b/testes/cstack.lua
@@ -20,13 +20,14 @@
-- get and print original limit
-local origlimit = debug.setcstacklimit(400)
+local origlimit <const> = debug.setcstacklimit(400)
print("default stack limit: " .. origlimit)
+
-- Do the tests using the original limit. Or else you may want to change
-- 'currentlimit' to lower values to avoid a seg. fault or to higher
-- values to check whether they are reliable.
-local currentlimit = origlimit
+local currentlimit <const> = origlimit
debug.setcstacklimit(currentlimit)
print("current stack limit: " .. currentlimit)
@@ -107,12 +108,16 @@
do print("testing changes in C-stack limit")
+ -- Just an alternative limit, different from the current one
+ -- (smaller to avoid stack overflows)
+ local alterlimit <const> = currentlimit * 8 // 10
+
assert(not debug.setcstacklimit(0)) -- limit too small
assert(not debug.setcstacklimit(50000)) -- limit too large
local co = coroutine.wrap (function ()
- return debug.setcstacklimit(400)
+ return debug.setcstacklimit(alterlimit)
end)
- assert(co() == false) -- cannot change C stack inside coroutine
+ assert(not co()) -- cannot change C stack inside coroutine
local n
local function foo () n = n + 1; foo () end
@@ -123,28 +128,32 @@
return n
end
- -- set limit to 400
- assert(debug.setcstacklimit(400) == currentlimit)
- local lim400 = check()
+ -- set limit to 'alterlimit'
+ assert(debug.setcstacklimit(alterlimit) == currentlimit)
+ local limalter <const> = check()
-- set a very low limit (given that there are already several active
-- calls to arrive here)
- local lowlimit = 38
- assert(debug.setcstacklimit(lowlimit) == 400)
- assert(check() < lowlimit - 30)
- assert(debug.setcstacklimit(600) == lowlimit)
- local lim600 = check()
- assert(lim600 == lim400 + 200)
+ local lowlimit <const> = 38
+ assert(debug.setcstacklimit(lowlimit) == alterlimit)
+ -- usable limit is much lower, due to active calls
+ local actuallow = check()
+ assert(actuallow < lowlimit - 30)
+ -- now, add 'lowlimit' extra slots, which should all be available
+ assert(debug.setcstacklimit(lowlimit + lowlimit) == lowlimit)
+ local lim2 <const> = check()
+ assert(lim2 == actuallow + lowlimit)
-- 'setcstacklimit' works inside protected calls. (The new stack
-- limit is kept when 'pcall' returns.)
assert(pcall(function ()
- assert(debug.setcstacklimit(400) == 600)
- assert(check() <= lim400)
+ assert(debug.setcstacklimit(alterlimit) == lowlimit * 2)
+ assert(check() <= limalter)
end))
- assert(check() == lim400)
- assert(debug.setcstacklimit(origlimit) == 400) -- restore original limit
+ assert(check() == limalter)
+ -- restore original limit
+ assert(debug.setcstacklimit(origlimit) == alterlimit)
end
