Re: [RFC] libstdc++/6720 and libstdc++/6671

[Zack Weinberg <zack at codesourcery dot com>]

On Thu, May 23, 2002 at 01:30:32AM -0300, Alexandre Oliva wrote:
> 
> My suggestion is that, whenever a *system* header file includes
> another header file using angle brackets, we search only the system
> header files (or perhaps search them first).
> 
> Then, -I flags won't get bits/bar.h accidentally replaced, but
> -isystem will still allow users to do it if they really mean it.

I could get behind this.  It's a straightforward change and easy to
document.

Here's a challenge: does this idea get rid of the need for "quoted
includes" in fixincludes?  If not, can you make it do so?

Here's a second: What should double-quote includes do in system
headers?  Can you make this work so that -I- doesn't break system
headers?

> It seems to me that the
> only way to overcome this problem is to have the preprocessor know a
> list of standard headers, that, when included with angle brackets, it
> would search in -I directories, but warn instead of including them.

I am opposed to any change involving wiring a list of headers into the
preprocessor, because it would only raise a debate about which headers
should be on the list, with the "correct" answer varying with both the
standards of interest and the operating system in use.

zw