diff --git a/headers/private/print/libprint/PackBits.h b/headers/private/print/libprint/PackBits.h
index faf4ec5083..2d17ca9169 100644
--- a/headers/private/print/libprint/PackBits.h
+++ b/headers/private/print/libprint/PackBits.h
@@ -6,6 +6,7 @@
 #ifndef __PACKBITS_H
 #define __PACKBITS_H
 
-int	pack_bits(unsigned char *out, unsigned char *in, int bytes);
+int	pack_bits_size(const unsigned char *in, int bytes);
+int	pack_bits(unsigned char *out, const unsigned char *in, int bytes);
 
 #endif	/* __PACKBITS_H */