diff --git a/vlib/os/const.v b/vlib/os/const.v
new file mode 100644
index 0000000000..336f661e2d
--- /dev/null
+++ b/vlib/os/const.v
@@ -0,0 +1,75 @@
+module os
+
+const (
+	FILE_SHARE_READ   = 1
+	FILE_SHARE_WRITE  = 2
+	FILE_SHARE_DELETE = 4
+)
+
+const (
+	FILE_NOTIFY_CHANGE_FILE_NAME   = 1
+	FILE_NOTIFY_CHANGE_DIR_NAME    = 2
+	FILE_NOTIFY_CHANGE_ATTRIBUTES  = 4
+	FILE_NOTIFY_CHANGE_SIZE        = 8
+	FILE_NOTIFY_CHANGE_LAST_WRITE  = 16
+	FILE_NOTIFY_CHANGE_LAST_ACCESS = 32
+	FILE_NOTIFY_CHANGE_CREATION    = 64
+	FILE_NOTIFY_CHANGE_SECURITY    = 128
+)
+
+const (
+	FILE_ACTION_ADDED              = 1
+	FILE_ACTION_REMOVED            = 2
+	FILE_ACTION_MODIFIED           = 3
+	FILE_ACTION_RENAMED_OLD_NAME   = 4
+	FILE_ACTION_RENAMED_NEW_NAME   = 5
+)
+
+const (
+	FILE_ATTR_READONLY                 = 0x1
+	FILE_ATTR_HIDDEN                   = 0x2
+	FILE_ATTR_SYSTEM                   = 0x4
+	FILE_ATTR_DIRECTORY                = 0x10
+	FILE_ATTR_ARCHIVE                  = 0x20
+	FILE_ATTR_DEVICE                   = 0x40
+	FILE_ATTR_NORMAL                   = 0x80
+	FILE_ATTR_TEMPORARY                = 0x100
+	FILE_ATTR_SPARSE_FILE              = 0x200
+	FILE_ATTR_REPARSE_POINT            = 0x400
+	FILE_ATTR_COMPRESSED               = 0x800
+	FILE_ATTR_OFFLINE                  = 0x1000
+	FILE_ATTR_NOT_CONTENT_INDEXED      = 0x2000
+	FILE_ATTR_ENCRYPTED                = 0x4000
+	FILE_ATTR_INTEGRITY_STREAM         = 0x8000
+	FILE_ATTR_VIRTUAL                  = 0x10000
+	FILE_ATTR_NO_SCRUB_DATA            = 0x20000
+	// FILE_ATTR_RECALL_ON_OPEN        = u32(0x...)
+	// FILE_ATTR_RECALL_ON_DATA_ACCESS = u32(0x...)
+)
+
+const (
+	FILE_TYPE_DISK = 0x1
+	FILE_TYPE_CHAR = 0x2
+	FILE_TYPE_PIPE = 0x3
+
+	FILE_TYPE_UNKNOWN = 0x0
+)
+
+const (
+	FILE_INVALID_FILE_ID = (-1)
+)
+
+// (Must be realized in Syscall) (Must be specified)
+// File modes.
+
+const (
+    O_RDONLY = 1 // open the file read-only.
+    O_WRONLY = 2 // open the file write-only.
+    O_RDWR   = 3 // open the file read-write.
+
+    O_APPEND = 8   // append data to the file when writing.
+    O_CREATE = 16  // create a new file if none exists.
+    O_EXCL   = 32  // used with O_CREATE, file must not exist.
+    O_SYNC   = 64  // open for synchronous I/O.
+    O_TRUNC  = 128 // truncate regular writable file when opened.
+)