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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Peter Maydell" <peter.maydell@linaro.org>,
	"Alex Bennée" <alex.bennee@linaro.org>
Cc: QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [PATCH] qemu/atomic.h: add #ifdef guards for stdatomic.h
Date: Thu, 26 Mar 2020 19:05:41 +0100
Message-ID: <ba33454a-6e57-960a-7114-fc71a9f09442@redhat.com> (raw)
In-Reply-To: <CAFEAcA8Lo84gNk2tFCKsgM_O50bXTCs6Z9jH6aCvfDA56TDCmA@mail.gmail.com>

On 26/03/20 18:14, Peter Maydell wrote:
>> +#ifndef atomic_fetch_add
>>  #define atomic_fetch_add(ptr, n) __atomic_fetch_add(ptr, n, __ATOMIC_SEQ_CST)
>>  #define atomic_fetch_sub(ptr, n) __atomic_fetch_sub(ptr, n, __ATOMIC_SEQ_CST)
>>  #define atomic_fetch_and(ptr, n) __atomic_fetch_and(ptr, n, __ATOMIC_SEQ_CST)
>>  #define atomic_fetch_or(ptr, n)  __atomic_fetch_or(ptr, n, __ATOMIC_SEQ_CST)
>>  #define atomic_fetch_xor(ptr, n) __atomic_fetch_xor(ptr, n, __ATOMIC_SEQ_CST)
>> +#endif
>
> This will work around FreeBSD's current implementation in particular,
> but I don't think there's anything in the C11 spec that mandates that
> atomic_fetch_add() and friends have to be macros and not simply
> functions...

That's not a problem as long as they are all functions, the macros would
simply override the function-based implementation.

Paolo



  parent reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26 17:01 Alex Bennée
2020-03-26 17:14 ` Peter Maydell
2020-03-26 17:32   ` Alex Bennée
2020-03-26 18:05   ` Paolo Bonzini [this message]
2020-03-26 20:19     ` Peter Maydell
2020-03-27  9:51       ` Alex Bennée
2020-03-27 13:35         ` Richard Henderson
2020-03-26 19:58 ` Richard Henderson
2020-03-26 20:05   ` Paolo Bonzini

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