diff --git a/ChangeLog b/ChangeLog
index 309bde6034..69e08ece20 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat May  7 22:38:04 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* thread.c (rb_fd_init): remove volatile qualifier.
+
 Sat May  7 22:34:29 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* thread.c (rb_fd_init_copy): new internal api. It provide efficient
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 84a8a46ed1..781f4ce78f 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -244,7 +244,7 @@ typedef struct {
     fd_set *fdset;
 } rb_fdset_t;
 
-void rb_fd_init(volatile rb_fdset_t *);
+void rb_fd_init(rb_fdset_t *);
 void rb_fd_term(rb_fdset_t *);
 void rb_fd_zero(rb_fdset_t *);
 void rb_fd_set(int, rb_fdset_t *);
@@ -263,7 +263,7 @@ typedef struct {
     fd_set *fdset;
 } rb_fdset_t;
 
-void rb_fd_init(volatile rb_fdset_t *);
+void rb_fd_init(rb_fdset_t *);
 void rb_fd_term(rb_fdset_t *);
 #define rb_fd_zero(f)		((f)->fdset->fd_count = 0)
 void rb_fd_set(int, rb_fdset_t *);
diff --git a/thread.c b/thread.c
index 90c2765447..55236b7f8e 100644
--- a/thread.c
+++ b/thread.c
@@ -2320,7 +2320,7 @@ rb_thread_priority_set(VALUE thread, VALUE prio)
  */
 
 void
-rb_fd_init(volatile rb_fdset_t *fds)
+rb_fd_init(rb_fdset_t *fds)
 {
     fds->maxfd = 0;
     fds->fdset = ALLOC(fd_set);
@@ -2437,7 +2437,7 @@ rb_fd_select(int n, rb_fdset_t *readfds, rb_fdset_t *writefds, rb_fdset_t *excep
 #elif defined(_WIN32)
 
 void
-rb_fd_init(volatile rb_fdset_t *set)
+rb_fd_init(rb_fdset_t *set)
 {
     set->capa = FD_SETSIZE;
     set->fdset = ALLOC(fd_set);