Re: What is the purpose of 'warning: no newline at end of file'?

["Neo Anderson" <neo_in_matrix at msn dot com>]

Thanks, that makes things much clearer for me.

----Original Message Follows----
From: Jonathan Turkanis <technews@kangaroologic.com>
To: gcc-help@gcc.gnu.org
Subject: Re: What is the purpose of 'warning: no newline at end of file'?
Date: Wed, 06 Jul 2005 22:40:28 -0600

[Sorry Neo, I think I sent you personal email accidentally]

Neo Anderson wrote:

> So, what is the purpose of this warning? What possible 'damages' does 
this warning protect against?


I believe this language was added to the standard because at the time some 
systems were not able to handle files properly if they didn't end in a 
newline. This wording made it possible to provide conforming C++ 
implementations for those platforms.

I'm not sure if there still are any such systems, but because the standard 
has given implementations to freedom to do whatever they want (that's what 
undefined behavior means) if you tell them to process a file not ending in a 
newline, be warned that if you try to compile your code on another system, 
the compiler may refuse. I know, for example, that Comeau in strict mode 
won't compile it. For that matter, neither will gcc with -pedantic-errors.

Jonathan

> And, what is the 'the behavior'?
>
> ----Original Message Follows----
> From: Jonathan Turkanis <technews@kangaroologic.com>
> To: gcc-help@gcc.gnu.org
> Subject: Re: What is the purpose of 'warning: no newline at end of file'?
> Date: Wed, 06 Jul 2005 21:41:20 -0600
>
> Neo Anderson wrote:
>
>> I don't even think it's a problem. Why do I need (or better have) a line 
ending?
>
>
>
> The C++ standard says: If a source file that is not empty does not end in 
a newline character, or ends in a newline character immediately preceded by 
a backslash character, the behavior is undefined. (2.1/1)
>
> Jonathan
>
>
>
>