From: Russell Shaw <rjshaw@netspace.net.au>
To: gdb@sourceware.org, Andreas Schwab <schwab@linux-m68k.org>
Subject: Re: sizeof
Date: Wed, 11 May 2022 01:48:50 +1000 [thread overview]
Message-ID: <6772c7d9-8242-2946-3a74-9e6b05f9daf8@netspace.net.au> (raw)
In-Reply-To: <dc776675-488f-52f7-3b67-9ccf8c59fcca@netspace.net.au>
Andreas Schwab wrote:
>On Mai 11 2022, Russell Shaw wrote:
>
>> On 10/5/22 5:22 pm, Andreas Schwab wrote:
>>> On Mai 10 2022, Russell Shaw wrote:
>>>
>>>>> Andreas Schwab wrote:
>>>>> On Mai 09 2022, Russell Shaw wrote:
>>>>>
>>>>>> sizeof(int()) should transform to sizeof(int (*)()) according to the
C++20 standard.
>>>>>
>>>>> No, see [expr.sizeof] #3.
>>>>
>>>> What does "[expr.sizeof] #3" refer to ?
>>> Paragrph #3 in section [expr.sizeof].
>>> "The lvalue-to-rvalue (7.3.1), array-to-pointer (7.3.2), and
>>> function-to-pointer (7.3.3) standard conversions are not applied to
>>> the operand of sizeof."
>>
>> "Standard conversions" are only applied to expressions, not type-id (which
>> is an abstract declarator syntax).
>
>So what's the chapter and verse for your claim?
It is not spelt out, but implied from the context.
Clearly, the standard conversions are only a meaningful concept for expressions.
"int()" is not an expression, but a type-id for a function pointer "int(*)()"
so "sizeof(int())" == "size of ptr to function"
unary-expression :
...
sizeof unary-expression
sizeof ( type-id )
next prev parent reply other threads:[~2022-05-10 15:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-08 15:22 sizeof Russell Shaw
2022-05-08 17:29 ` sizeof Simon Marchi
2022-05-08 17:48 ` sizeof Andreas Schwab
2022-05-09 7:21 ` sizeof Russell Shaw
2022-05-09 7:35 ` sizeof Andreas Schwab
2022-05-10 3:46 ` sizeof Russell Shaw
2022-05-10 7:22 ` sizeof Andreas Schwab
2022-05-10 14:20 ` sizeof Russell Shaw
2022-05-10 14:48 ` sizeof Andreas Schwab
2022-05-10 15:43 ` sizeof Russell Shaw
2022-05-10 15:48 ` Russell Shaw [this message]
2022-05-10 16:06 ` sizeof Andreas Schwab
2022-05-11 5:38 ` sizeof Russell Shaw
2022-05-11 8:16 ` sizeof Russell Shaw
2022-05-11 17:44 ` sizeof Russell Shaw
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