diff --git a/include/ucore/bitvec.h b/include/ucore/bitvec.h
index a3e224b..bb5dfe1 100644
--- a/include/ucore/bitvec.h
+++ b/include/ucore/bitvec.h
@@ -71,7 +71,7 @@ void uc_bv_set_all(struct UCBitVec *v);
  * int a[] = {0,1,1,1,0};
  * set_bits_from_array(v,a,5);
  * */
-void uc_bv_set_bits_from_array(struct UCBitVec *v,char *array,size_t array_len);
+void uc_bv_set_bits_from_array(struct UCBitVec *v,const char *array,size_t array_len);
 
 
 #ifdef __cplusplus
diff --git a/src/bitvec.c b/src/bitvec.c
index 8286d36..cd73536 100644
--- a/src/bitvec.c
+++ b/src/bitvec.c
@@ -63,7 +63,7 @@ void uc_bv_set_bit(struct UCBitVec *v,int b)
    v->vec[bit_index(b)] |= 1UL << (bit_offset(b)); 
 }
 
-void uc_bv_set_bits_from_array(struct UCBitVec *v,char *array,size_t array_len)
+void uc_bv_set_bits_from_array(struct UCBitVec *v,const char *array,size_t array_len)
 {
     size_t i;