diff --git a/buffer.c b/buffer.c
index f18e0320f89a881914c74bca373d2ef3bcb91a7a..fe875412679b1806fac1bdcee41ef0be924a3ac7 100644
--- a/buffer.c
+++ b/buffer.c
@@ -126,5 +126,5 @@ int
 nettle_buffer_copy(struct nettle_buffer *dst,
 		   const struct nettle_buffer *src)
 {
-  nettle_buffer_write(dst, src->size, src->contents);
+  return nettle_buffer_write(dst, src->size, src->contents);
 }