Re: [Qemu-devel] Headers without multiple inclusion guards

[Laszlo Ersek]

On 06/05/19 16:23, Daniel P. Berrangé wrote:
> On Tue, May 28, 2019 at 08:12:24PM +0200, Markus Armbruster wrote:
>> We have a bunch of headers without multiple inclusion guards.  Some are
>> clearly intentional, some look accidental.  Too many for me to find out
>> by examining each of them, so I'm asking their maintainers.
>>
>> Why do I ask?  I'd like to mark the intentional ones and fix the
>> accidental ones, so they don't flunk "make check-headers" from "[RFC v4
>> 0/7] Baby steps towards saner headers" just because they lack multiple
>> inclusion guards.
>>
>> Just in case: what's a multiple inclusion guard?  It's
>>
>>     #ifndef UNIQUE_GUARD_SYMBOL_H
>>     #define UNIQUE_GUARD_SYMBOL_H
>>     ...
>>     #endif
>>
>> with nothing but comments outside the conditional, so that the header
>> can safely be included more than once.
> 
> Any opinions on using the less verbose syntax instead:
> 
>   #pragma once
> 
> It is not portable C, but we explicitly only care about GCC or CLang,
> so portability isn't an issue for us.

I don't feel strongly about this particular question, so if folks prefer
"#pragma once", I won't complain. I'd just like to report that section 6
of "HACKING" appears the opposite of "we explicitly only care about GCC
or CLang".

Thanks,
Laszlo

> 
> 
>> Cryptography
>> M: Daniel P. Berrange <address@hidden>
>> crypto/ivgen-essiv.h
>> crypto/ivgen-plain.h
>> crypto/ivgen-plain64.h
> 
> These have header guards present
> 
>> tests/crypto-tls-psk-helpers.h
>> tests/crypto-tls-x509-helpers.h
> 
> These should be fixed.
> 
> Regards,
> Daniel
>