Re: Newbie question - M4 header guard

[Gary V . Vaughan]

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Hi Brian,

Thanks for your interest in m4.

On 13 Jul 2004, at 21:41, Dick, Brian wrote:
> We have been using the cpp preprocessor for our Oracle PL/SQL code and 
> have run into some limitations. So, we are considering converting to 
> the m4 preprocessor. For the most part the conversion has been 
> straight forward and is working great. However, we are not sure how to 
> implement the m4 equivalent to the C header guard convention. I 
> searched Google for an answer and came up empty.
>
> How would I do the following with m4:
>
> #ifndef _MY_MACRO_
> #define _MY_MACRO_
> …
>  #end if

ifelse(_MY_MACRO_, `1', `',
`define(`_MY_MACRO_', `1')dnl
...
')dnl

As always with m4, be careful with the quoting :-)

> Also, is there a newsgroup where we can discuss m4 issues?

There are a bunch of mailing lists, all quite low volume,
though I'm planning a new major release in the coming months,
and such things usually spark some lively discussion.

address@hidden is for bug reports
address@hidden is for general discussion
address@hidden is where potential patches to the m4 code are worked 
through
address@hidden collects commit notifications from the code repository

There are archives of these lists at, for example:

   http://lists.gnu.org/pipermail/m4-discuss

and you can sign up for the mailing list at, for example:

   http://lists.gnu.org/mailman/listinfo/m4-commit

HTH,
        Gary.
- --
Gary V. Vaughan      ())_.  address@hidden,gnu.org}
Research Scientist   ( '/   http://tkd.kicks-ass.net
GNU Hacker           / )=   http://www.gnu.org/software/libtool
Technical Author   `(_~)_   http://sources.redhat.com/autobook

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