Index: include/ruby/win32.h
===================================================================
--- include/ruby/win32.h	(revision 32136)
+++ include/ruby/win32.h	(working copy)
@@ -235,6 +235,8 @@
 extern rb_pid_t  rb_w32_pipe_exec(const char *, const char *, int, int *, int *);
 extern int    flock(int fd, int oper);
 extern int    rb_w32_has_cancel_io(void);
+extern int    rb_w32_add_socket(SOCKET, int);
+extern void   rb_w32_remove_socket(int);
 extern int    rb_w32_is_socket(int);
 extern int    WSAAPI rb_w32_accept(int, struct sockaddr *, int *);
 extern int    WSAAPI rb_w32_bind(int, const struct sockaddr *, int);
Index: win32/win32.c
===================================================================
--- win32/win32.c	(revision 32136)
+++ win32/win32.c	(working copy)
@@ -2177,6 +2177,26 @@
 }
 #endif
 
+int
+rb_w32_add_socket(SOCKET sock, int flag)
+{
+    int fd = rb_w32_open_osfhandle(sock, O_RDWR|O_BINARY|O_NOINHERIT);
+    if (fd != -1) {
+        st_insert(socklist, (st_data_t)sock, (st_data_t)flag);
+    }
+    return fd;
+}
+
+void
+rb_w32_remove_socket(int fd)
+{
+    SOCKET sock = TO_SOCKET(fd);
+    st_data_t key = (st_data_t)sock;
+    st_delete(socklist, &key, NULL);
+    _set_osfhnd(fd, (SOCKET)INVALID_HANDLE_VALUE);
+    _close(fd);
+}
+
 #undef getsockopt
 
 static int