Re: backslash whitespace newline

[Howard Hinnant <howard dot hinnant at gmail dot com>]

On Oct 25, 2005, at 8:11 PM, Joe Buck wrote:

> > // A poorly formatted comment \\
> > int x = 0;
> > int y = 1;
> > ...
>
> Howard,
>
> Have you tested the sequence above with various compilers?

I only know of the results on gcc 4.x, MS, EDG-based, and Freescale  
CodeWarrior.

> I just
> have.  The behavior depends on whether there is whitespace after the
> \\ or not.  If there is none, then EDG-based compilers will comment
> out the declaration of x.  If there is whitespace, gcc 3.x comments
> it out and the others don't.

Right, that's exactly the issue.

> I personally like the fact that gcc's
> behavior does not depend on invisible characters; on the other hand,
> there's a good argument that this behavior is ordinarily not desirable
> and should be warned about, except to continue strings.
>
> I have difficulty believing that it is desirable for production code
> to contain surprises like this.

Personally I'd fire a programmer that depended on the presence of  
whitespace after a '\'.  It is implementation defined behavior, and  
invisible in the source at that (in most editors).  I've seen code  
broken both by gcc's behavior, and by other compiler's behavior by  
depending on what happens when whitespace is included after a '\'.

And it is not my assertion that gcc's behavior is better or worse  
than other compilers.  Only that gcc's behavior is unique in the  
industry (I actually haven't tried all other modern compilers) and  
that uniqueness in this way is not an asset to gcc.

-Howard