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From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: "void **" : Is it valid and what does it mean?
Message-ID: <16292@smoke.brl.mil>
Date: 29 May 91 07:27:39 GMT
References: <AJ3U.91May27213633@jade.cs.virginia.edu> <6001@goanna.cs.rmit.oz.au> <1991May28.115914.19879@email.tuwien.ac.at>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 7

By the way, there is no need to go through a lot of gyrations to attain
the originally-stated goal.  Just declare the parameter as a void * anyway,
and apply the appropriate cast inside the function where it is used.  E.g.
	void foo(void *param) { ++(*(struct msg **)param)->field; }
After all, the thing pointed to, in this case a "struct msg *", is also an
object and so a pointer to it (a "struct msg **") can be fairly
conveniently converted to void* and back.