Index: head/share/man/man9/printf.9
===================================================================
--- head/share/man/man9/printf.9
+++ head/share/man/man9/printf.9
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 8, 2006
+.Dd November 18, 2015
 .Dt PRINTF 9
 .Os
 .Sh NAME
@@ -41,9 +41,13 @@
 .Fn tprintf "struct proc *p" "int pri" "const char *fmt" ...
 .Ft int
 .Fn uprintf "const char *fmt" ...
+.Ft int
+.Fn vprintf "const char *fmt" "va_list ap"
 .In sys/syslog.h
 .Ft void
 .Fn log "int pri" "const char *fmt" ...
+.Ft void
+.Fn vlog "int pri" "const char *fmt" "va_list ap"
 .Sh DESCRIPTION
 The
 .Xr printf 9
Index: head/sys/kern/subr_prf.c
===================================================================
--- head/sys/kern/subr_prf.c
+++ head/sys/kern/subr_prf.c
@@ -302,9 +302,15 @@
 	va_list ap;
 
 	va_start(ap, fmt);
-	(void)_vprintf(level, log_open ? TOLOG : TOCONS | TOLOG, fmt, ap);
+	vlog(level, fmt, ap);
 	va_end(ap);
+}
+
+void
+vlog(int level, const char *fmt, va_list ap)
+{
 
+	(void)_vprintf(level, log_open ? TOLOG : TOCONS | TOLOG, fmt, ap);
 	msgbuftrigger = 1;
 }
 
Index: head/sys/sys/systm.h
===================================================================
--- head/sys/sys/systm.h
+++ head/sys/sys/systm.h
@@ -207,6 +207,7 @@
 	    __va_list) __printflike(1, 0);
 void	log(int, const char *, ...) __printflike(2, 3);
 void	log_console(struct uio *);
+void	vlog(int, const char *, __va_list) __printflike(2, 0);
 int	asprintf(char **ret, struct malloc_type *mtp, const char *format, 
 	    ...) __printflike(3, 4);
 int	printf(const char *, ...) __printflike(1, 2);