func (d *dev) Drain() (err error) {
err = sys.IoctlTermios(d.Fd(), sys.TCSETSW, &d.tsav) // drain and set parameters
if err != nil {
err = d.error("drain", err)
}
return
}
// Open a local serial port.
// Inictl is an optional string containing one ore more commands in Ctl() style
func Open(filename string, inictl string) (port Port, err error) {
var file *os.File
// NONBLOCK prevents Open from blocking
// until DCD is asserted from modem
if file, err = os.OpenFile(filename, os.O_RDWR|syscall.O_NOCTTY|syscall.O_NONBLOCK, 0); err != nil {
return
}
p := new(dev)
p.File = file
p.name = filename
p.encaps = p
fd := file.Fd()
err = setBlocking(fd)
if err != nil {
err = p.error("set blocking", err)
}
t := &p.t
if err = sys.IoctlTermios(fd, sys.TCGETS, t); err != nil {
err = p.error("get term attr", err)
return
}
p.tOrig = p.t
p.tsav = p.t
t.Cflag |= sys.CLOCAL
t.Lflag &^= sys.ICANON | sys.ECHO | sys.ISIG | sys.IEXTEN
t.Iflag &^= sys.BRKINT | sys.ICRNL | sys.INPCK | sys.ISTRIP | sys.IXON
t.Iflag |= sys.IGNPAR
t.Oflag &^= sys.OPOST
// timeout 1/10s after the last byte (at least one) has been read
t.Cc[sys.VMIN] = 1
t.Cc[sys.VTIME] = 1
if err = p.Ctl(initDefault, inictl); err != nil {
return
}
port = p
return
}
func (d *dev) updateCtl() (err error) {
if d.inCtl {
return
}
t := &d.t
tsav := &d.tsav
if t.Cflag == tsav.Cflag &&
t.Lflag == tsav.Lflag &&
t.Oflag == tsav.Oflag &&
t.Cc[sys.VTIME] == tsav.Cc[sys.VTIME] &&
t.Cc[sys.VMIN] == tsav.Cc[sys.VMIN] {
return
}
if err = sys.IoctlTermios(d.Fd(), sys.TCSETSW, t); err == nil { // drain and set parameters
d.tsav = d.t
// It seems changing parameters also resets DTR/RTS lines;
// put in the previously requested states again:
d.SetRts(d.rts)
d.SetDtr(d.dtr)
}
return
}
func (p *dev) Close() error {
sys.IoctlTermios(p.Fd(), sys.TCSETSW, &p.tOrig)
return p.hw.Close()
}