diff --git a/include/ar.h b/include/ar.h
new file mode 100644
index 0000000..cd538fa
--- /dev/null
+++ b/include/ar.h
@@ -0,0 +1,17 @@
+#define	ARMAG	"!<arch>\n"
+#define	SARMAG	8
+
+#define	ARFMAG	"`\n"
+#define SARNAME	16
+
+struct	ar_hdr
+{
+	char	name[SARNAME];
+	char	date[12];
+	char	uid[6];
+	char	gid[6];
+	char	mode[8];
+	char	size[10];
+	char	fmag[2];
+};
+#define	SAR_HDR	(SARNAME+44)