diff --git a/lib/capn-malloc.c b/lib/capn-malloc.c
index 3d8093e..7a2977c 100644
--- a/lib/capn-malloc.c
+++ b/lib/capn-malloc.c
@@ -215,7 +215,7 @@ static int header_render(struct capn *c, struct capn_segment *seg, uint32_t *hea
 	return 0;
 }
 
-int capn_write_mem_packed(struct capn *c, uint8_t *p, size_t sz)
+static int capn_write_mem_packed(struct capn *c, uint8_t *p, size_t sz)
 {
 	struct capn_segment *seg;
 	struct capn_ptr root;
diff --git a/lib/capnp_c.h b/lib/capnp_c.h
index 30d0b21..40d88f0 100644
--- a/lib/capnp_c.h
+++ b/lib/capnp_c.h
@@ -209,6 +209,7 @@ int capn_setv64(capn_list64 p, int off, const uint64_t *data, int sz);
  * datasz is in bytes, ptrs is # of pointers, sz is # of elements in the list
  * On an error a CAPN_NULL pointer is returned
  */
+capn_ptr capn_new_string(struct capn_segment *seg, const char *str, ssize_t sz);
 capn_ptr capn_new_struct(struct capn_segment *seg, int datasz, int ptrs);
 capn_ptr capn_new_interface(struct capn_segment *seg, int datasz, int ptrs);
 capn_ptr capn_new_ptr_list(struct capn_segment *seg, int sz);