isnewcclosure - Mintlify Starter Kit

Tells you whether a function is a newcclosure-wrapped C closure.

isnewcclosure(func: function): boolean

Most commonly used to filter getgc() or filtergc() output down to wrapped Luau functions - the hooks and disguises another script left behind. A C function made by roblox and a newcclosure-wrapped one both return true from iscclosure. isnewcclosure is the only built-in predicate that separates the two.

Parameters

Parameter	Type	Description
`func`	`function`	The function to check.

Returns

true if func was produced by newcclosure, false otherwise. A plain Luau function, a real Roblox C function like print, and the executor’s own C closures all return false.

Example

<<<<<<< HEAD
local isNewC = isnewcclosure(print)
=======
-- isnewcclosure(func: function): boolean
>>>>>>> 50e30f53759b0538759af25c9b271514aa2c9290

local wrapped, builtin = 0, 0
for _, fn in ipairs(getgc()) do
    if type(fn) == "function" and iscclosure(fn) then
        if isnewcclosure(fn) then
            wrapped += 1
        else
            builtin += 1
        end
    end
end

print(`wrapped Luau: {wrapped}, engine builtins: {builtin}`)

Used to verify if a C function is native or a wrapped Lua function.