t.Fatalf("want %q got %q, err=%v", "", string(s), err)
	}
	if _, err := buf.Peek(1); err != io.EOF {
		t.Fatalf("want EOF got %v", err)
	}

	// Test for issue 3022, not exposing a reader's error on a successful Peek.
	buf = NewReaderSize(dataAndEOFReader("abcd"), 32)
	if s, err := buf.Peek(2); string(s) != "ab" || err != nil {
		t.Errorf(`Peek(2) on "abcd", EOF = %q, %v; want "ab", nil`, string(s), err)

// people are used to seeing in C.  For generated Go code, such as
// package syscall's data structures, we drop a common prefix
// (so sec, usec, which will get turned into Sec, Usec for exporting).
func fieldPrefix(fld []*ast.Field) string {
	prefix := ""
	for _, f := range fld {
		for _, n := range f.Names {
			// Ignore field names that don't have the prefix we're