Re: declaration specifiers wooziness

[Josh Triplett <josht@linux.vnet.ibm.com>]

On Wed, 2007-06-27 at 16:16 +0100, Derek M Jones wrote:
> Alex, Josh,
> 
> > On Wed, 2007-06-27 at 14:33 +0400, Alexey Dobriyan wrote:
> >> sparse silently accepts some peculiar combinations of declaration
> >> specifiers:
> 
> These are all permitted by the syntax of C.
> 
> 6.7 Declarations, the init-declarator-list is optional.

Huh; interesting.  That explains "int volatile;" as well; it doesn't
parse as an attempt to declare an integer named volatile, but as a
declaration with no variable.

> >> "typedef extern;" passes.
> ...
> >> Not sure how many different bugs there are here, though...
> 
> Sparse might flag the usage as suspicious, but it is not a bug.

Probably not worth the trouble of flagging.

> > Several more:
> 
> The syntax permits:
> 
> signed unsigned short long double int;

I would hope it does not permit "double int".

Sparse will in fact spew errors about *that* syntax:
/dev/stdin:1:8: error: You cannot have both signed and unsigned modifiers.
/dev/stdin:1:17: error: You cannot have both signed and unsigned modifiers.
/dev/stdin:1:23: error: You cannot have both long and short modifiers.
/dev/stdin:1:23: error: You cannot have both signed and unsigned modifiers.
/dev/stdin:1:28: error: modifier [signed] [unsigned] is invalid in this context
/dev/stdin:1:28: error: You cannot have both signed and unsigned modifiers.
/dev/stdin:1:35: error: Trying to use reserved word 'int' as identifier

- Josh Triplett