diff --git a/Objects/stringobject.c b/Objects/stringobject.c
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -882,9 +882,9 @@
             size -= chunk_size;
         }
 #ifdef __VMS
-        if (size) fwrite(data, (int)size, 1, fp);
+        if (size) fwrite(data, (size_t)size, 1, fp);
 #else
-        fwrite(data, 1, (int)size, fp);
+        fwrite(data, 1, (size_t)size, fp);
 #endif
         Py_END_ALLOW_THREADS
         return 0;
@@ -2332,7 +2332,7 @@
 }
 
 Py_LOCAL_INLINE(Py_ssize_t)
-countchar(const char *target, int target_len, char c, Py_ssize_t maxcount)
+countchar(const char *target, Py_ssize_t target_len, char c, Py_ssize_t maxcount)
 {
     Py_ssize_t count=0;
     const char *start=target;