Mega Code Archive
Va_arg, variable argument lists
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#include <stdio.h>
#include <stdarg.h>
void foo(char *fmt, ...);
int main(void) {
int i = 50;
char str[] = "jeronimo";
char x = 'a';
printf(" foo prints: ");
foo("d", i);
printf(" foo prints: ");
foo("s", str);
printf(" foo prints: ");
foo("c", x);
return 0;
}
void foo(char *fmt, ...) {
va_list ap;
int d;
char c, *s;
va_start(ap, fmt);
while (*fmt)
switch(*fmt++) {
case 's': /* string */
s = va_arg(ap, char *);
printf("string %s\n", s);
break;
case 'd': /* int */
d = va_arg(ap, int);
printf("int %d\n", d);
break;
case 'c': /* char */
/* need a cast here since va_arg only takes fully promoted types */
c = (char) va_arg(ap, int);
printf("char %c\n", c);
break;
}
va_end(ap);
}
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