1 files changed, 30 insertions, 7 deletions

diff --git a/ext/io/wait/wait.c b/ext/io/wait/wait.c
index df8d24c29b..fcb3bcfe42 100644
--- a/ext/io/wait/wait.c
+++ b/ext/io/wait/wait.c
@@ -50,6 +50,23 @@ io_ready_p(io)
     return Qnil;
 }
 
+struct wait_readable_arg {
+    rb_fdset_t fds;
+    struct timeval *timeout;
+};
+
+#ifdef HAVE_RB_FD_INIT
+static VALUE
+wait_readable(p)
+    VALUE p;
+{
+    struct wait_readable_arg *arg = (struct wait_readable_arg *)p;
+    rb_fdset_t *fds = &arg->fds;
+
+    return (VALUE)rb_thread_select(rb_fd_max(fds), rb_fd_ptr(fds), NULL, NULL, arg->timeout);
+}
+#endif
+
 /*
 =begin
 --- IO#wait([timeout])
@@ -64,27 +81,33 @@ io_wait(argc, argv, io)
     VALUE io;
 {
     OpenFile *fptr;
-    fd_set rd;
+    struct wait_readable_arg arg;
     int fd, n;
     VALUE timeout;
-    struct timeval *tp, timerec;
+    struct timeval timerec;
 
     GetOpenFile(io, fptr);
     rb_io_check_readable(fptr);
     rb_scan_args(argc, argv, "01", &timeout);
     if (NIL_P(timeout)) {
-	tp = 0;
+	arg.timeout = 0;
     }
     else {
 	timerec = rb_time_interval(timeout);
-	tp = &timerec;
+	arg.timeout = &timerec;
     }
 
     if (rb_io_read_pending(fptr)) return Qtrue;
     fd = fptr->fd;
-    FD_ZERO(&rd);
-    FD_SET(fd, &rd);
-    if (rb_thread_select(fd + 1, &rd, NULL, NULL, tp) < 0)
+    rb_fd_init(&arg.fds);
+    rb_fd_set(fd, &arg.fds);
+#ifdef HAVE_RB_FD_INIT
+    n = (int)rb_ensure(wait_readable, (VALUE)&arg,
+		       (VALUE (*)_((VALUE)))rb_fd_term, (VALUE)&arg.fds);
+#else
+    n = rb_thread_select(fd + 1, rb_fd_ptr(&rd), NULL, NULL, tp)
+#endif
+    if (n < 0)
 	rb_sys_fail(0);
     rb_io_check_closed(fptr);
     if (ioctl(fptr->fd, FIONREAD, &n)) rb_sys_fail(0);