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Date: Tue, 2 Feb 2016 22:46:07 -0500
From: Kevin Easton <kevin@guarana.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Aleksa Sarai <cyphar@cyphar.com>, xypron.glpk@gmx.de,
        Tejun Heo <tj@kernel.org>, koct9i@gmail.com, ebiederm@xmission.com,
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        peterz@infradead.org, Ingo Molnar <mingo@kernel.org>,
        akpm@linux-foundation.org, kirill.shutemov@linux.intel.com
Subject: Re: [PATCH] kernel/fork.c: use sizeof() instead of sizeof
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On Tue, Feb 02, 2016 at 05:04:06PM +0000, Al Viro wrote:
 
> FWIW, the actual rules are
> 	unary-expression: postfix-expression |
> 			  ++ unary-expression |
> 			  -- unary-expression |
> 			  - cast-expression |
> 			  + cast-expression |
> 			  ! cast-expression |
> 			  ~ cast-expression |
> 			  * cast-expression |
> 			  & cast-expression |
> 			  sizeof unary-expression |
> 			  sizeof ( type-name )
> 	cast-expression: unary-expression |
> 			 ( type-name ) cast-expression
> Note that while e.g.
> 	++ ++ n
> is allowed by grammar, it runs afoul of the constraint for ++ argument, which
> must be a modifiable lvalue.  None of the operators above yield that, so
> the rules for ++ and -- might as well have been ++ postfix-expression and
> -- postfix-expression resp.

Unless I'm mistaken, * cast-expression yields an lvalue.

    - Kevin