diff --git a/src/fuse_open.cpp b/src/fuse_open.cpp
index 09781586..09f96782 100644
--- a/src/fuse_open.cpp
+++ b/src/fuse_open.cpp
@@ -299,7 +299,7 @@ namespace FUSE
     if(rv != 0)
       return rv;
 
-    uint64_t x = _(cfg->passthrough,ffi_->flags);
+    const uint64_t x = _(cfg->passthrough,ffi_->flags);
     switch(x)
       {
       case _(PassthroughEnum::ro,O_RDONLY):