From 4a1415dcda4c02fb965719815b6da023148908df Mon Sep 17 00:00:00 2001
From: Cheer Xiao <xiaqqaix@gmail.com>
Date: Mon, 17 Mar 2014 22:39:57 +0800
Subject: [PATCH] Much better sys.SetNonblock...

---
 edit/reader.go |  2 +-
 sys/fcntl.go   | 13 +++++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/edit/reader.go b/edit/reader.go
index 6d453b9b..a95ef9a9 100644
--- a/edit/reader.go
+++ b/edit/reader.go
@@ -66,7 +66,7 @@ type Reader struct {
 }
 
 func NewReader(f *os.File) *Reader {
-	if err := sys.SetNonblock(int(f.Fd())); err != nil {
+	if err := sys.SetNonblock(int(f.Fd()), true); err != nil {
 		panic(err)
 	}
 	rd := &Reader{
diff --git a/sys/fcntl.go b/sys/fcntl.go
index 1bbd1db8..76a29dcb 100644
--- a/sys/fcntl.go
+++ b/sys/fcntl.go
@@ -19,7 +19,16 @@ func GetNonblock(fd int) (bool, error) {
 	return r&syscall.O_NONBLOCK != 0, err
 }
 
-func SetNonblock(fd int) error {
-	_, err := Fcntl(fd, syscall.F_SETFL, syscall.O_NONBLOCK)
+func SetNonblock(fd int, nonblock bool) error {
+	r, err := Fcntl(fd, syscall.F_GETFL, 0)
+	if err != nil {
+		return err
+	}
+	if nonblock {
+		r |= syscall.O_NONBLOCK
+	} else {
+		r &^= syscall.O_NONBLOCK
+	}
+	_, err = Fcntl(fd, syscall.F_SETFL, r)
 	return err
 }