Has TRUE always had a non-zero value?

Question

I have a co-worker that maintains that TRUE used to be defined as 0 and all other values were FALSE. I could swear that every language I\'ve worked with, if you could even

Answer 1

It's easy to get confused when bash's true/false return statements are the other way around:

$ false; echo $?
1
$ true; echo $?
0

Answer 2

General rule:

1. Shells (DOS included) use "0" as "No Error"... not necessarily true.

2. Programming languages use non-zero to denote true.

That said, if you're in a language which lets your define TRUE of FALSE, define it and always use the constants.

Answer 3

In any language I've ever worked in (going back to BASIC in the late 70s), false has been considered 0 and true has been non-zero.

Answer 4

In languages like C there was no boolean value so you had to define your own. Could they have worked on a non-standard BOOL overrides?