[Qemu-devel] Re: [PATCH] scripts: add a guard macro in generated .h files

[Tristan Gingold]

On Feb 21, 2011, at 9:14 AM, Paolo Bonzini wrote:

> On 02/21/2011 07:42 AM, Tristan Gingold wrote:
>> Mostly a style issue.  It is common to always protect header files
>> against multiple inclusion, unless the header is meant to be included
>> several times (which is not the case for these config files).  I
>> think this is a good practice.
> 
> Traditionally, autoconf's config.h headers have no guards either.  This can 
> indeed cause some troubles.  However, it also helps highlighting poor 
> practices, such as libraries installing a config.h file including it from a 
> public header.
> 
>> I once got redefinition warnings for macros in config-host.h, but I
>> agree that adding the guard macro doesn't fix this issue.
> 
> config-host.h should always be the first included header (we are poor at 
> this) and its macros should never conflict with anything else.  I think we 
> should rather fix the problems you've seen with config-host.h, if you can 
> still reproduce them.

Thank you.  I will investigate the next time I have the issue and the time.

Tristan.