Re: [Groff] Is _M considered an internal register of -me?

[Werner LEMBERG]

From: "James J. Ramsey" <address@hidden>
Subject: [Groff] Is _M considered an internal register of -me?
Date: Mon, 6 Jan 2003 09:43:46 -0800 (PST)

> I wanted to redefine the ".$c" macro in -me to print chapter
> headings the way I wanted them printed.  However, I noticed that by
> default ".$c" used the _M register, which is used by the ".++" macro
> to indicate whether one is in the prefatory matter section, the
> chapter section, appendix section, etc.  I was thinking of using the
> _M register in my redefined ".$c" macro for the same purpose, but I
> wasn't sure that _M was a "safe" register to use, that is, a
> register that I can count on existing from version to version of
> -me.  I have not found any reference to register _M in the -ME
> Reference Manual, nor in the man page.  So far as I can tell, it
> seems to be solely for internal use, yet it is used in macros that
> are intended to be redefined.
> 
> Can I count on the _M register to remain in at least the groff
> version of the -me macros, Or should I write a ".$c" macro under the
> assumption that _M may not always be available?

I've now documented the `_M' register, making it `official'.  Thanks
for the report, and sorry for the really late fix.

It will be avaivable in the CVS as soon as I can commit again.


    Werner