diff --git a/src/c/ffi/mmap.d b/src/c/ffi/mmap.d
index eea75b5e4..583653236 100644
--- a/src/c/ffi/mmap.d
+++ b/src/c/ffi/mmap.d
@@ -50,7 +50,7 @@
                 len = ecl_to_unsigned_integer(length);
                 stream = Cnil;
         } else {
-                c_flags = MAP_FILE;
+                c_flags = MAP_SHARED;
                 stream = cl_open(13, filename,
                                  @':direction', direction,
                                  @':element-type', element_type,