bug#12098: How to trap errors in man?

[Juri Linkov]

> In a discussion on gnu-prog-discuss today, there was an attempt to
> script Emacs as a standalone info reader. It was also desired to make
> it format man pages (like the standalone info reader) for programs
> that don't have an info manual.

The Emacs Info reader can format man pages with the help
of info-man.el.

> Personally, I'd just rip out all the asynchronous stuff and make "man"
> synchronous (I have man set to "bully" mode in my setup), but I am
> guessing that would be an unpopular change,

Yes, the delay when the whole session is freezing during formatting would
be undesirable.  The current situation with asynchronous popping up buffers
is not perfect either.  In bug#9084 we are trying to improve this by
modifying man.el to work more like async shell commands.

> so I'm wondering if there's some other way to make it possible to use
> man synchronously and/or allow man's caller to find out about errors.

You can use `Man-cooked-hook' that is called at the end of
`Man-bgproc-sentinel'.  In this hook you can check whether the value of
`Man-page-list' is nil.