[tex-k] Uninterruptible loop in web2c TeX

[Igor Liferenko]

Hi Reinhard ,

> after pressing Ctrl+C, did you do what the message said?

Here is the full transcript:

$ tex
This is TeX, Version 3.14159265 (TeX Live 2020/Debian) (preloaded format=tex)
**\relax

*^C! Interruption.
<*>

? (Please type a command or say `\end')
*(Please type a command or say `\end')
*(Please type a command or say `\end')
*(Please type a command or say `\end')
<ad infinitum>

>  Did you enter "\end"?

It does not allow me to enter `\end' because it seems it always reads
EOF from stdin.

> Please try
>
>   1) run `tex'
>   2) type `\relax' and <return>
>   3) press Ctrl+C
>   4) type \end
>
> Does this work?

It is not supposed to work, because after Ctrl+C I get the `?' prompt,
and `\end' can be entered only in `*' prompt.

Igor