//go:build linux || darwin || freebsd || netbsd || openbsd || dragonfly

package main

import (
	"os"
	"syscall"
	"unsafe"
)

// termWidth returns the width of the terminal f, and false when f is not a
// terminal: TIOCGWINSZ fails on anything else.
func termWidth(f *os.File) (int, bool) {
	var ws struct{ rows, cols, x, y uint16 }
	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, f.Fd(), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&ws)))
	if errno != 0 {
		return 0, false
	}
	return int(ws.cols), true
}