Re: How to reliably edit a file from within Emacs Lisp and return a string?

[Eli Zaretskii]

> Date: Sat, 24 Aug 2019 14:19:24 +0200
> From: Jean Louis <bugs@gnu.support>
> Cc: GNU Emacs Help <help-gnu-emacs@gnu.org>
> 
> Thanks for helping. I am reading string from PostgreSQL database
> field. And I wish to edit that string. It is best done if string is
> first written into the file, so that I can edit the file, and after
> killing the buffer to read the string from file, so that it can be fed
> into the database.

That can be done easily, but I cannot resist asking: why do you need
the intermediate temporary file?  Why not insert the string into a
buffer, let the user edit that string in a buffer, and then have a
command in that buffer that tells you the user is done editing?

As for feeding the string into the database: can you tell in more
detail how you are doing that?  Are you invoking some external program
passing it the edited string, for example?

> Question is basically how to know, from Emacs Lisp, reliably, that
> process of editing of a buffer finished, so that string can be read
> from file, thereafter.

The best way is for the user to tell you so.  Only the user knows for
sure, right?