diff --git a/racket/src/racket/src/port.c b/racket/src/racket/src/port.c
index 44f719b039..063e3d8d41 100644
--- a/racket/src/racket/src/port.c
+++ b/racket/src/racket/src/port.c
@@ -4792,8 +4792,8 @@ static intptr_t fd_get_string_slow(Scheme_Input_Port *port,
 
   while (1) {
     /* Loop until a read succeeds. */
-    int none_avail = 0;
-    int target_size, target_offset, ext_target;
+    int none_avail = 0, ext_target;
+    intptr_t target_size, target_offset;
     char *target;
     Scheme_Object *sema;