nil. This is different from blank, which is considered a character string, and different from 0, which is a number. So, in addition to checking a variable for its current value, you can test to determine if the variable has been assigned a value.
An AutoLISP variable that has not been assigned a value is said to benil when their values are no longer needed. Setting a variable to nil releases the memory used to store that variable's value. If you no longer need the val variable, you can release its value from memory with the following expression:
Each variable consumes a small amount of memory, so it is good programming practice to reuse variable names or set variables to_$ (setq val nil)
nil
Local Variables in Functions on this topic.
Another efficient programming practice is to use local variables whenever possible. SeeThe server encountered an internal error or misconfiguration and was unable to complete your request.
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