[U-Boot-Users] [PATCH 02/17] examples/eepro100_eeprom: Fix memcpy to return destination pointer

Jean-Christophe PLAGNIOL-VILLARD plagnioj at jcrosoft.com
Mon May 19 03:22:11 CEST 2008


On 01:03 Mon 19 May     , Wolfgang Denk wrote:
> In message <20080518222019.GC19480 at game.jcrosoft.org> you wrote:
> >
> > > >  static inline void *memcpy(void *dst, const void *src, unsigned int len)
> > > >  {
> > > >  	char *ret = dst;
> > > > +
> > > >  	while (len-- > 0) {
> > > >  		*ret++ = *((char *)src);
> > > >  		src++;
> > > >  	}
> > > > -	return (void *)ret;
> > > > +
> > > > +	return (void *)dst;
> > > 
> > > While technically correct, this is bogus. We have a variable ret, but
> > > we don't return it. And we have a variable dst, but we don't use it as
> > > destination pointer.
> > > 
> > > Please change the
> > > 	*ret++ = *((char *)src);
> > > into
> > > 	*dst++ = *((char *)src);
> > > and leave all the rest.
> > You can not do this because dst is a void
> 
> Why not? src is void, too.
gcc will claim about the cast.

we can do this
       void *ret = dst;
       char *d = dst;
       const char *s = src;

       while (len-- > 0)
               *d++ = *s++;

        return ret;

Best Regards,
J.




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