c types problem

Joseph S. D. Yao jsdy at hadron.UUCP
Mon Jan 6 03:45:00 AEST 1986

In article <870 at kuling.UUCP> gostas at 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;
which can be #define'd:
#define retmix(val,type)	retval.type = val; return(retval);
=>			retmix(Xxx, mix_i);

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

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