// chance the file doesn't exist yet - keeps the number of tries in
// TempFile to a minimum.
//
//go:linkname runtime_rand runtime.rand
func runtime_rand() uint64

func nextRandom() string {
	return itoa.Uitoa(uint(uint32(runtime_rand())))
}

// CreateTemp creates a new temporary file in the directory dir,
// opens the file for reading and writing, and returns the resulting file.

	fdSem <- true
	defer func() { <-fdSem }()

	nextRandom := func() string {
		return strconv.Itoa(rand.Int())
	}

	dir, base := filepath.Split(filename)
	var (
		bakname string
		f       *os.File
	)
	for {
		bakname = filepath.Join(dir, base+"."+nextRandom())
		var err error
		f, err = os.OpenFile(bakname, os.O_RDWR|os.O_CREATE|os.O_EXCL, perm)