diff --git a/include/sdsl/bits.hpp b/include/sdsl/bits.hpp
index a390b8a7..250f280d 100644
--- a/include/sdsl/bits.hpp
+++ b/include/sdsl/bits.hpp
@@ -199,7 +199,7 @@ struct bits {
     static uint32_t hi11(uint64_t x);
 
     //! Writes value x to an bit position in an array.
-    static void write_int(uint64_t* word, uint64_t x, const uint8_t offset=0, const uint8_t len=64);
+    static void write_int(uint64_t* word, uint64_t x, uint8_t offset=0, const uint8_t len=64);
 
     //! Writes value x to an bit position in an array and moves the bit-pointer.
     static void write_int_and_move(uint64_t*& word, uint64_t x, uint8_t& offset, const uint8_t len);