Re: The caselessness is one of the things I like best!

["David Thompson" <david.thompson1@worldnet.att.net>]

Jeffrey Carter <jeffrey.carter@boeing.com> wrote :
...
> I have used C compilers that do not give warnings for undeclared
> variables by default; they are silently created as type int. I don't
> know if this is still legal for standard C.
>
Not variables.  It has never been legal, even in early Unix C,
to have undeclared variables.  What was legal before and in C89
was to declare a variable without specifying the type, or a function
without specifying the return type, and it defaulted to (signed) int.
Usually this meant specifying the storage-class instead, but ISTR
at least some compilers did allow at least at file-scope (and maybe
in a struct) a declaration consisting only of the identifier or declarator.
This is called "implicit int" and is removed in C99, and in C++.

It was legal before and in C89 to use a _function_ name without
a declaration and it was treated as if declared "int x()", that is,
function of unspecified but non-default-promotable non-variadic
arguments returning int.  This also is removed in C99, and in C++.

(In both cases it was probably the omission from C++ that made it
politically acceptable for WG14/J11 to drop them from C, even though
these changes break significant existing and in the former case
arguably reasonable code, normally a taboo.)

--
- David.Thompson 1 now at worldnet.att.net