bug#61667: 29.0.60; Failure to redisplay

[Eli Zaretskii]

> Date: Thu, 23 Feb 2023 06:36:54 +0800
> From: Po Lu <Luangruo@yahoo.com>
> CC: 61667@debbugs.gnu.org
> 
> That won't work, unfortunately -- this needs to check whether or not a 
> function is being called at all, and not just the value of some flags at the 
> time we update the frame title.

If you only want to know whether a function was called, how about
adding a variable to which those calls (where you wanted to add
printf's) will add indications each time the function is called?
Like, for example, a char [] array to which those places would add
some simple text?

But I admit that I have only a vague idea of what you are trying to
establish, so perhaps if I understood it better, I could suggest
better methods of logging this information without incurring
Shrödinger-cat like effects.