1 files changed, 1 insertions, 1 deletions
diff --git a/gr-blocks/lib/file_source_impl.h b/gr-blocks/lib/file_source_impl.h
index bec21ea8ab..a39190de8f 100644
--- a/gr-blocks/lib/file_source_impl.h
+++ b/gr-blocks/lib/file_source_impl.h
@@ -32,7 +32,7 @@ namespace blocks {
 class BLOCKS_API file_source_impl : public file_source
 {
 private:
-    size_t d_itemsize;
+    const size_t d_itemsize;
     uint64_t d_start_offset_items;
     uint64_t d_length_items;
     uint64_t d_items_remaining;