1 #include "a.h"
2 
3 void
4 warn(char *fmt, ...)
5 {
6 	va_list arg;
7 
8 	va_start(arg, fmt);
9 	fprint(2, "warning: ");
10 	vfprint(2, fmt, arg);
11 	fprint(2, "\n");
12 	va_end(arg);
13 }