diff --git a/ChangeLog b/ChangeLog
index 2d3d1c0d8f..4034ff1536 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Mar 20 12:43:12 2011  Tanaka Akira  <akr@fsij.org>
+
+	* ext/openssl/ruby_missing.h: parenthesize macro arguments.
+
 Tue Mar 22 13:33:22 2011  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
 
 	* ext/openssl/lib/openssl/buffering.rb: removed circular require of
diff --git a/ext/openssl/ruby_missing.h b/ext/openssl/ruby_missing.h
index 64b76f26b4..1c5d05baca 100644
--- a/ext/openssl/ruby_missing.h
+++ b/ext/openssl/ruby_missing.h
@@ -12,11 +12,11 @@
 #define _OSSL_RUBY_MISSING_H_
 
 #define rb_define_copy_func(klass, func) \
-	rb_define_method(klass, "initialize_copy", func, 1)
+	rb_define_method((klass), "initialize_copy", (func), 1)
 
 
 #ifndef GetReadFile
-#define FPTR_TO_FD(fptr) (fptr->fd)
+#define FPTR_TO_FD(fptr) ((fptr)->fd)
 #else
 #define FPTR_TO_FD(fptr) (fileno(GetReadFile(fptr)))
 #endif
@@ -28,14 +28,14 @@
 #ifndef HAVE_RB_STR_SET_LEN
 /* these methods should probably be backported to 1.8 */
 #define rb_str_set_len(str, length) do {	\
-	RSTRING(str)->ptr[length] = 0;		\
-	RSTRING(str)->len = length;		\
+	RSTRING(str)->ptr[(length)] = 0;		\
+	RSTRING(str)->len = (length);		\
 } while(0)
 #endif /* ! HAVE_RB_STR_SET_LEN */
 
 #ifndef HAVE_RB_BLOCK_CALL
 /* the openssl module doesn't use arg[3-4] and arg2 is always rb_each */
-#define rb_block_call(arg1, arg2, arg3, arg4, arg5, arg6) rb_iterate(rb_each, arg1, arg5, arg6)
+#define rb_block_call(arg1, arg2, arg3, arg4, arg5, arg6) rb_iterate(rb_each, (arg1), (arg5), (arg6))
 #endif /* ! HAVE_RB_BLOCK_CALL */
 
 #endif /* _OSSL_RUBY_MISSING_H_ */