Re: Text copied from *grep* buffer has NUL (0x00) characters

[Eli Zaretskii]

> From: "R. Diez" <rdiezmail-emacs@yahoo.de>
> Cc: help-gnu-emacs@gnu.org
> Date: Sun, 9 May 2021 20:47:28 +0200
> 
> Emacs is already checking all bytes on save. I inserted an invalid sequence 
> and got this warning on save:

That's not the same.  the warning you saw is triggered by a failure to
convert to the external encoding, so it consumes no extra CPU cycles.
Null bytes will not fail anything, so you should test for them
explicitly (and in some encodings, like UTF-16, they are necessary and
cannot be avoided).