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//go:build linux || freebsd || netbsd || openbsd || illumos
// +build linux freebsd netbsd openbsd illumos
package beeep
import (
"errors"
"os"
"syscall"
"time"
"unsafe"
)
// Constants
const (
// This number represents the fixed frequency of the original PC XT's timer chip, which is approximately 1.193 MHz. This number
// is divided with the desired frequency to obtain a counter value, that is subsequently fed into the timer chip, tied to the PC speaker.
clockTickRate = 1193180
// linux/kd.h, start sound generation (0 for off)
kiocsound = 0x4B2F
// linux/input-event-codes.h
evSnd = 0x12 // Event type
sndTone = 0x02 // Sound
)
var (
// DefaultFreq - frequency, in Hz, middle A
DefaultFreq = 440.0
// DefaultDuration - duration in milliseconds
DefaultDuration = 200
)
// inputEvent represents linux/input.h event structure.
type inputEvent struct {
Time syscall.Timeval // time in seconds since epoch at which event occurred
Type uint16 // event type
Code uint16 // event code related to the event type
Value int32 // event value related to the event type
}
// ioctl system call manipulates the underlying device parameters of special files.
func ioctl(fd, name, data uintptr) error {
_, _, e := syscall.Syscall(syscall.SYS_IOCTL, fd, name, data)
if e != 0 {
return e
}
return nil
}
// Beep beeps the PC speaker (https://en.wikipedia.org/wiki/PC_speaker).
//
// On Linux it needs permission to access `/dev/tty0` or `/dev/input/by-path/platform-pcspkr-event-spkr` files for writing,
// and `pcspkr` module must be loaded. User must be in correct groups, usually `input` and/or `tty`.
//
// If it can not open device files, it will fallback to sending Bell character (https://en.wikipedia.org/wiki/Bell_character).
// For bell character in X11 terminals you can enable bell with `xset b on`. For console check `setterm` and `--blength` or `--bfreq` options.
//
// On macOS this just sends bell character. Enable `Audible bell` in Terminal --> Preferences --> Settings --> Advanced.
//
// On Windows it uses Beep function via syscall.
//
// On Web it plays hard coded beep sound.
func Beep(freq float64, duration int) error {
if freq == 0 {
freq = DefaultFreq
} else if freq > 20000 {
freq = 20000
} else if freq < 0 {
freq = DefaultFreq
}
if duration == 0 {
duration = DefaultDuration
}
period := int(float64(clockTickRate) / freq)
var evdev bool
f, err := os.OpenFile("/dev/tty0", os.O_WRONLY, 0644)
if err != nil {
e := err
f, err = os.OpenFile("/dev/input/by-path/platform-pcspkr-event-spkr", os.O_WRONLY, 0644)
if err != nil {
e = errors.New("beeep: " + e.Error() + "; " + err.Error())
// Output the only beep we can
_, err = os.Stdout.Write([]byte{7})
if err != nil {
return errors.New(e.Error() + "; " + err.Error())
}
return nil
}
evdev = true
}
defer f.Close()
if evdev { // Use Linux evdev API
ev := inputEvent{}
ev.Type = evSnd
ev.Code = sndTone
ev.Value = int32(freq)
d := *(*[unsafe.Sizeof(ev)]byte)(unsafe.Pointer(&ev))
// Start beep
f.Write(d[:])
time.Sleep(time.Duration(duration) * time.Millisecond)
ev.Value = 0
d = *(*[unsafe.Sizeof(ev)]byte)(unsafe.Pointer(&ev))
// Stop beep
f.Write(d[:])
} else { // Use ioctl
// Start beep
err = ioctl(f.Fd(), kiocsound, uintptr(period))
if err != nil {
return err
}
time.Sleep(time.Duration(duration) * time.Millisecond)
// Stop beep
err = ioctl(f.Fd(), kiocsound, uintptr(0))
if err != nil {
return err
}
}
return nil
}
|
