diff --git a/src/basicio.cpp b/src/basicio.cpp
index d377e6d2..aa4fdbc9 100644
--- a/src/basicio.cpp
+++ b/src/basicio.cpp
@@ -283,7 +283,7 @@ byte* FileIo::mmap(bool isWriteable) {
   if (error()) {
     throw Error(ErrorCode::kerCallFailed, path(), strError(), "FileIo::mmap");
   }
-  p_->pMappedArea_ = buf->first;
+  p_->pMappedArea_ = buf.data();
   p_->isMalloced_ = true;
 #endif
   return p_->pMappedArea_;