daleske@cbdkc1.UUCP (08/22/86)
[ I'll see if I can write up a quicky example of varargs usage. -JDD ]
Here is my implemintation of varargs.h for os9/68k. Since the only
documentation I have on varargs is not in the public domain, I can't post
it. (Remove the signature at the end before using.) I use tabs set every
8 characters. If you get "line too long" errors, check to see if the tabs
were converted to spaces somewhere along the line.
/* varargs.h for os9/68k by Robert A. Larson */
/* version 0 for os9/68k C 2.0 04/20/86 */
/* varargs is a "portable" way to write a routine that takes a variable */
/* number of arguements. This implemination agrees with both the 4.2bsd*/
/* and Sys V documentation of varargs. Note that just because varargs.h*/
/* is used does not mean that it is used properly. */
/* Ignore the "expression with little effect" warnings. (compiler bug) */
#define va_alist _va_arg1, _va_arg2, _va_arg3
#define va_dcl unsigned _va_arg1, _va_arg2, _va_arg3;
typedef struct {
unsigned _va_at; /* number of arguments used, 0, 1, or more */
/* (double as first arg counts as 2) */
union {
struct {
unsigned _va_uns1, _va_uns2;
} _va_uuns;
double _va_udouble;
} _va_union;
char *_va_pointer;
} va_list;
#define va_start(pvar) ( (pvar)._va_at = 0, \
(pvar)._va_union._va_uuns._va_uns1 = _va_arg1,\
(pvar)._va_union._va_uuns._va_uns2 = _va_arg2,\
(pvar)._va_pointer = (char *) &_va_arg3 \
)
#define va_arg(pvar, type) ( \
((pvar)._va_at++) ? ( \
((pvar)._va_at == 2) ? ( \
(sizeof(type) == 8) ? ( \
*(((type *)((pvar)._va_pointer))++) \
) : (type)( \
(pvar)._va_union._va_uuns._va_uns2 \
) \
) : ( \
*(((type *)((pvar)._va_pointer))++) \
) \
) : ( \
(sizeof(type) == 8) ? (type)( \
(pvar)._va_at++, \
(pvar)._va_union._va_udouble \
) : (type)( \
(pvar)._va_union._va_uuns._va_uns1 \
) \
) \
)
#define va_end(pvar) /* va_end is simple */
--
Bob Larson
Arpa: Blarson@Usc-Eclb.Arpa or blarson@usc-oberon.arpa
Uucp: (ihnp4,hplabs,tektronix)!sdcrdcf!usc-oberon!blarson