Message Box Question

[pinkman]

In HPPL there is no “void” return value. If you don’t specify a return value with the RETURN statement, then the return value of the last function called is used as a return value.
To avoid side effects with user key definition, you have to return -1.
More details here: https://www.hpmuseum.org/forum/thread-14929.html

The second argument of MSGBOX is True or False, 1 or 0, TRUE or FALSE, true or false.
Don’t write the brackets, they are used in the documentation to show that the argument is optional.