Return value from a macro

[Dolf Grunbauer]

In article <7727 at pt.cs.cmu.edu> mwm at a.gp.cs.cmu.edu (Mark Maimone) writes:
]In article <960 at pyrite4.UUCP> Larry Baltz writes:
]>The problem I'm having is trying to have the macro return a value of the 
]>deleted link.
]	You can just use the comma operator to return a value (the value of
]a comma-expression is the last item in the list).  Here's one solution:
]
]#define delete_head(head) ((header->next == header) ? NULL : \
]	(dh_temp = (head)->next, dh_temp->next->prev = (head), \
]	(head)->next = dh_temp->next, dh_temp))
]
]static LINK dh_temp;

Oke, but note that the solution of Mark doesn't work when the code is supposed
to be shared by other processes at the same time. E.g. in a kernel or a 
shared library there probably will only be one dh_temp for all processes
thus (due to scheduling cq process switching) it is likely that these processes
ruin the value of dh_temp, creating very hard to trace errors/bugs/panics.
-- 
Dolf Grunbauer          Tel: +31 55 433233  Internet dolf at idca.tds.philips.nl
Philips Telecommunication and Data Systems  UUCP ....!mcvax!philapd!dolf
Dept. SSP, P.O. Box 245, 7300 AE Apeldoorn, The Netherlands         n   n   n
It's a pity my .signature is too small to show you my solution of  a + b = c