Aw: Re: Supressing output from AC_CHECK_DECL

[jcurlmail]

> Hello Jason, all,
> 
> * address@hidden wrote on Tue, May 08, 2007 at 02:46:53PM CEST:
> > 
> > When I use AC_CHECK_DECL, how can I prevent it from outputting to the
> > console for a specific message only? I don't want to supress all
> > messages, only one specific message (and replace it with my own, more
> > complex reusable macro).
> 
> Hmm.  Reimplementing AC_CHECK_DECL may be easier than trying to use it,
> as Noah already indicated.  Especially, I think if you need to work
> around the output, then it seems likely that you will also need to work
> around caching as well: if you check for the same symbol more than once,
> with different code snippets then it will skew your results.  (Which
> begs the question whether your identical double checking of timeradd in
> the macro you posted was intentional.)

In the original post, the 'timeradd' twice was unintentional but the double 
check of localtime_r wasn't (visible with Solaris 9 and Interix 3.5), tiemradd 
was there to test ideas on more convenient platforms but I forgot to remove it 
earlier. And you're right, I had to work around caching as well, by unsetting 
the environment variable.

> 
> > In the end, I've done:
> > pushdef([AS_MESSAGE_FD], [/dev/null])
> > popdef([AS_MESSAGE_FD])
> 
> First, be encouraged to use m4_pushdef rather than pushdef, etc.
> But also this ends up generating code like
>   echo "$message" >&/dev/null
> 
> which is not portable:
> 
> $ ksh -c 'echo >&/dev/null'
> ksh: >&/dev/null : illegal file descriptor name

Thinking about it, it'll probably be better to implement the guts of 
AC_DECL_CHECK here instead of using all the workarounds as Noah had already 
mentioned.

Thanks,
Jason.