diff --git a/include/osmocom/core/bitvec.h b/include/osmocom/core/bitvec.h
index c3c1153..19e2af8 100644
--- a/include/osmocom/core/bitvec.h
+++ b/include/osmocom/core/bitvec.h
@@ -70,7 +70,7 @@
 			enum bit_value bit);
 int bitvec_set_bit(struct bitvec *bv, enum bit_value bit);
 int bitvec_get_bit_high(struct bitvec *bv);
-int bitvec_set_bits(struct bitvec *bv, enum bit_value *bits, unsigned int count);
+int bitvec_set_bits(struct bitvec *bv, const enum bit_value *bits, unsigned int count);
 int bitvec_set_uint(struct bitvec *bv, uint32_t in, unsigned int count);
 int bitvec_get_uint(struct bitvec *bv, unsigned int num_bits);
 int bitvec_find_bit_pos(const struct bitvec *bv, unsigned int n, enum bit_value val);