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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.lang.c
Subject: Re: c types problem
Message-ID: <168@hadron.UUCP>
Date: Sun, 5-Jan-86 12:45:00 EST
Article-I.D.: hadron.168
Posted: Sun Jan  5 12:45:00 1986
Date-Received: Tue, 7-Jan-86 06:53:08 EST
References: <870@kuling.UUCP>
Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao)
Organization: Hadron, Inc., Fairfax, VA
Lines: 38

In article <870@kuling.UUCP> gostas@kuling.UUCP (G|sta Simil{/ml) writes:
>The formal (but ugly) way to solve this would proparbly be to use a union
>for all (about 10) types. But now I wonder if anyone have a simpler but
>resonably portable solution?

I really don't think you'll find any more portable solution than to
use a union, which really isn't all that ugly if you declare the union
elsewhere and use some good macros.  E.g.:
	union mix {
		int	mix_i;
		long int mix_li;
		dev_t	mix_d;	/* Be sure to include dev_t and */
		time_t	mix_t;	/* time_t et al: they may surprise */
				/* you. */
		...
	};
	union mix getval(int);
	#define getint(x)	(getval((x)).mix_i)
	#define getlong(x)	(getval((x)).mix_li)
	...
If you're worried about portability, you certainly won't have any
places where you don't know the type of the return value.  Oh: to
return a value, in the function you really should (e.g.):
	union mix getval(x)
	  int x;
	{
		union mix retval;
		...
			retval.mix_i = Xxx;
			return(retval);
		...
	}
which can be #define'd:
#define retmix(val,type)	retval.type = val; return(retval);
=>			retmix(Xxx, mix_i);
-- 

	Joe Yao		hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}