ACL2-PC_colon__colon_ILLEGAL.html -- ACL2 Version 6.3

### ACL2-PC::ILLEGAL

(macro) `` illegal instruction

    Major Section:  PROOF-CHECKER-COMMANDS

    Example:
    (illegal -3)

    General Form:
    (illegal instruction)

Probably not of interest to most users; always ``fails'' since it expands to the `fail` command.

The `illegal` command is used mainly in the implementation. For example, the instruction `0` is ``read'' as `(illegal 0)`, since `dive` expects positive integers.