// initDefaultCache. cmd/go/main.go explicitly sets GOCACHE so that
	// subprocesses will inherit it, but that means initDefaultCache can't
	// otherwise distinguish between an explicit "off" and a UserCacheDir error.

	defaultDirOnce.Do(func() {
		defaultDir = cfg.Getenv("GOCACHE")
		if defaultDir != "" {
			defaultDirChanged = true
			if filepath.IsAbs(defaultDir) || defaultDir == "off" {
				return
			}

		log.Fatalf("link destination (%s) is not the same file as %s", dstAbs, targetPath)
	}

	// Output:
	// hello.link links to hello.txt
}

func ExampleUserCacheDir() {
	dir, dirErr := os.UserCacheDir()
	if dirErr == nil {
		dir = filepath.Join(dir, "ExampleUserCacheDir")
	}

	getCache := func(name string) ([]byte, error) {
		if dirErr != nil {

// On Plan 9, it returns /tmp.
//
// The directory is neither guaranteed to exist nor have accessible
// permissions.
func TempDir() string {
	return tempDir()
}

// UserCacheDir returns the default root directory to use for user-specific
// cached data. Users should create their own application-specific subdirectory
// within this one and use that.
//

pkg os, const ModeIrregular = 524288
pkg os, const ModeIrregular FileMode
pkg os, const ModeType = 2399666176
pkg os, func UserCacheDir() (string, error)
pkg os/signal, func Ignored(os.Signal) bool
pkg regexp/syntax, method (Op) String() string
pkg runtime/trace, func IsEnabled() bool
pkg runtime/trace, func Log(context.Context, string, string)

	t.Run("dir", testDoubleCloseError(sfdir))
}

func TestUserCacheDir(t *testing.T) {
	t.Parallel()

	dir, err := UserCacheDir()
	if err != nil {
		t.Skipf("skipping: %v", err)
	}
	if dir == "" {
		t.Fatalf("UserCacheDir returned %q; want non-empty path or error", dir)
	}

	fi, err := Stat(dir)
	if err != nil {
		if IsNotExist(err) {
			t.Log(err)
			return

		{"SyscallError", Type, 0},
		{"SyscallError.Err", Field, 0},
		{"SyscallError.Syscall", Field, 0},
		{"TempDir", Func, 0},
		{"Truncate", Func, 0},
		{"Unsetenv", Func, 4},
		{"UserCacheDir", Func, 11},
		{"UserConfigDir", Func, 13},
		{"UserHomeDir", Func, 12},
		{"WriteFile", Func, 16},
	},
	"os/exec": {
		{"(*Cmd).CombinedOutput", Method, 0},
		{"(*Cmd).Environ", Method, 19},