diff --git a/substrate/mmap b/substrate/mmap
index 00a8bc0..299ae9e 100644
--- a/substrate/mmap
+++ b/substrate/mmap
@@ -225,6 +225,8 @@ namespace substrate
 #ifdef _WIN32
 			if (_mapping)
 				CloseHandle(_mapping);
+			if (_fd != -1)
+				_close(_fd);
 #else
 			if (_fd != -1)
 				::close(_fd);