varargs functions: calling and prototyping

[Dave Eisen]

In article <1990Jul25.195944.9238 at DRD.Com> mark at drd.Com (Mark Lawrence) writes:
>
>I've got a function whose first three arguments should always be provided
>but the rest of the arguments will be handed to vsprintf for formatting.
>
>The function itself looks like:
>
[The K&R version of the function omitted for brevity]

#include <stdio.h>
#include <stdarg.h> /* varags is used in the K&R world, it doesn't work with
                       prototypes */
#include <alarms.h> /* which includes a function prototype for this func */

#define AlarmBufSz 1024
static char     buf[AlarmBufSz];

/* The definition of the function matches the prototype given in alarm.h */
/* This prototype is                                                     */
/* void ReportAlarm (char *source, AlarmType alarm, char *fmt, ...);     */

/*VARARGS3*/
void
ReportAlarm(char *source, AlarmType alarm, char *fmt, ...)
{
    va_list         args;

    va_start(args, format); /* va_start now takes the last required function
                               parameter as its second argumnet. */
    (void) vsprintf(buf, fmt, args);
    va_end(args);
/* Other stuff ... */
}




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