Real Documentation

Syntax

getupvalues(target: function | number): table

Aliases debug.getupvalues

Arguments

Name	Type	Description
`target`	`function \| number`	Lua function or stack level whose upvalues are returned.

Returns

Name	Type	Description
`upvalues`	`table`	One-based array table containing the function upvalues. Empty when none are present.

Description

Returns all upvalues from a Lua function or stack level as a one-based array table. Invalid stack levels raise "Level out of range", and non-Lua functions raise "Lua function expected". debug.getupvalues is an alias.

Call it with 1 parameter(s): target. The argument table explains which values are required and which ones only refine the behavior.

It returns upvalues (table). Use the returns table to separate successful values from nil results and recoverable errors.

Example

Read all upvalues from a Lua closure or stack level.

local first = "one"
local second = "two"

local function target()
    return first, second
end

local upvalues = getupvalues(target)

for index, value in ipairs(upvalues) do
    print(index, value)
end

print(#debug.getupvalues(target))