-stay_open mode, the `-charset filename=utf8` only work once

[HaujetZhao]

When using `-stay_open` mode, the `-charset filename=utf8` only work once.

I start the command with `exiftool  -stay_open True -@ -`, then I sent it args:

```
-createdate
文件01.jpg
-execute

-createdate
文件02.jpg
-execute
```

For the first file, it would be Okay, but when it comes to the second file, ExifTool will say the charset of the filename is not set.

Okay, I accept, so then I tried:

```
-charset filename=utf8
-createdate
文件01.jpg
-execute

-charset filename=utf8
-createdate
文件02.jpg
-execute
```

Then ExifTool will say `Warning: Tag 'charset' is not defined`

So I'm crushed. How can I set every filename their charset?

I think the there is a logic bug in the use of `-charset` when it comes to `-stay_open`.

[Phil Harvey]

This is FAQ 29

- Phil

[HaujetZhao]

This is FAQ 29

- Phil

Ah, my bad, sorry, haven't finish reading the FAQ, I'll study more. Thanks a lot!

[Phil Harvey]

I would suggest first reading the documentation for the option you are using (in this case -@) before checking the FAQ if you have a problem.

- Phil

[HaujetZhao]

I would suggest first reading the documentation for the option you are using (in this case -@) before checking the FAQ if you have a problem.

- Phil

Got it, thanks again!