Date: Sun, 06 May 2007 12:39:53 +0100 From: Mark Murray <markm@FreeBSD.ORG> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Missing LIST_PREV() ? Message-ID: <200705061139.l46BdssN017108@greatest.grondar.org> In-Reply-To: Message from Hans Petter Selasky <hselasky@c2i.net> of "Sun, 06 May 2007 13:04:04 %2B0200." <200705061304.05093.hselasky@c2i.net>
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Hans Petter Selasky writes: > Hi, > > Why should LISTs only be forward traversable? The following piece of > code make lists backward traversable: No objection to the concept. But... > /sys/sys/queue.h: > > +#define LIST_PREV(head,elm,field) \ > + (((elm) == LIST_FIRST(head)) ? ((__typeof(elm))0) : \ > + ((__typeof(elm))(((uint8_t *)((elm)->field.le_prev)) - \ > + ((uint8_t *)&LIST_NEXT((__typeof(elm))0,field))))) Please don't use typeof; it is a GCCism. Do you really mean NULL? M -- Mark R V Murray - Cert APS(Open) Dip Phys(Open) BSc Open(Open)
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