How return an error ?

[Girard Damien]

Hi all,

I am making some useful library for my softwares, and I have got one  
problem.

How I return an error ?

Because when I use "return", this doesn't work very great.

on hellotest theNumber
   if isnumber(theNumber) is false then
     return "error"
   end if
   ...
end hellotest

Thanks,

Girard Damien