[parisc-linux] gcc and ++

[Matthew Wilcox]

On Wed, Oct 02, 2002 at 09:30:03AM +0200, phi wrote:
> #define get_4(p) ( ((uint32)(*p++)<<24)| \
>                    ((uint32)(*p++)<<16)| \
>                    ((uint32)(*p++)<<8 )| \
>                    ((uint32)(*p++)) )

Undefined behaviour.  `|' is not a sequence point and you modify p more than
once.  How would this look?

#define get_4(p)	p += 4, (((uint32)p[-4] << 24) | \
			 ((uint32)p[-3] << 16) | \
			 ((uint32)p[-2] <<  8) | \
			 ((unit32)p[-1]))

comma _is_ a sequence point, so this is well-defined.

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