lock

Variables can be turned into constants using the lock command. Once a variable is locked, any assignment trying to change its value will result in a parsing error. This is valid for both scalar and string variables. It is not an error to try to lock a constant. A warning message will be given though. However, trying to lock an unexisting variable or something else than a constant or variable will result in an error.

lock var-list

C, cmode, unlock