1 files changed, 1 insertions, 1 deletions
diff --git a/ruby.h b/ruby.h
index bbd5819242..a2d7f981da 100644
--- a/ruby.h
+++ b/ruby.h
@@ -45,7 +45,7 @@ extern "C" {
 #define ISDIGIT(c) isdigit((unsigned char)(c))
 #define ISXDIGIT(c) isxdigit((unsigned char)(c))
 
-#ifndef __STDC__
+#if !defined(__STDC__) && !defined(_MSC_VER)
 # define volatile
 #endif