UpValueId returns a unique identifier for the upvalue numbered n from the closure at index f. Parameters f and n are as in UpValue (but n cannot be greater than the number of upvalues).

These unique identifiers allow a program to check whether different closures share upvalues. Lua closures that share an upvalue (that is, that access a same external local variable) will return identical ids for those upvalue indices.

UpValueId is referenced in 1 repository