From: Lars-Peter Clausen <lars@metafoo.de>
To: tangbin <tangbin@cmss.chinamobile.com>
Cc: Michael.Hennerich@analog.com, jic23@kernel.org, knaack.h@gmx.de,
pmeerw@pmeerw.net, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: adc: ad7768-1: Fix the right interrupt interfacecalls
Date: Wed, 12 May 2021 11:21:52 +0200 [thread overview]
Message-ID: <41d9dc0f-2e65-075f-9b57-740f31081860@metafoo.de> (raw)
In-Reply-To: <5dd97e8f-8a52-c79c-2b00-7e6b807990ed@cmss.chinamobile.com>
On 5/12/21 10:39 AM, tangbin wrote:
> Hi Lars-Peter:
>
> Thanks for you reply!
>
>> Hi,
>>
>> Thanks for the patch. Aren't those two expressions equivalent? Are
>> you seeing an issue with the current code? If so can you include that
>> in the commit message?
>>
>> - Lars
>>
>>
> When submitting this patch, I actually thought about it for a
> while, but finally decided to submit it, my reason is as follows:
>
> In numerical data of address, &ad7768_interrupt is equal to
> ad7768_interrupt, and the compilation can pass. But I think they are
> not the same, ad7768_interrupt is the first
>
> address of the function, and its type is irqreturn_t,
> &ad7768_interrupt represents the address of an object that points to
> the function ad7768_interrupt().
>
> So I think they are not the same, For previous experience with
> devm_request_irq(), I send this patch. If I'm wrong, I'm sorry to
> bother you.
>
Have a look at
https://stackoverflow.com/questions/6893285/why-do-function-pointer-definitions-work-with-any-number-of-ampersands-or-as
for some background on this.
You can also easily verify that they are the same with a simple test program
static void foo(void) {}
int main(void) {
printf("%p %p %d\n", foo, &foo, foo == &foo);
}
prev parent reply other threads:[~2021-05-12 9:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 15:31 [PATCH] iio: adc: ad7768-1: Fix the right interrupt interface calls Tang Bin
2021-05-11 16:29 ` Lars-Peter Clausen
2021-05-12 8:39 ` [PATCH] iio: adc: ad7768-1: Fix the right interrupt interfacecalls tangbin
2021-05-12 9:21 ` Lars-Peter Clausen [this message]
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