Re: Autoconf's main purpose is config.h generation that *just* has

[cs]

Thanks.  It really helped.

CS

_______________________________________

Dr. Christian Seberino
Gnumatica Scientific Software
8665 Lake Murray Blvd. #3
San Diego, CA 92119-2843
U.S.A.

Phone: (619) 393-9047
Email: address@hidden
WWW  : www.gnumatica.com
_______________________________________

 -------- Original Message --------
   Subject: Re: Autoconf's main purpose is config.h generation that *just*
   has   From: Ronald Landheer-Cieslak <address@hidden>
   Date: Thu, April 17, 2003 12:59 am
   To: address@hidden

   The *result* of the autoconf-generated configure script is "just a
   bunch  of defines".

   The configure.{ac|in} file is used to generate a shell-script that
   will be  used to scan the system for its abilities - at least, the
   ones you ask to  have checked. (That's where the "arbitrary shell
   code" is run). You could  effectively put shell code in the
   configure.{ac|in} file and thus have it  run at configure time.

   Anyways, the configure script uses a Makefile.in file (which might
   also  contain shell code to be run at compile-time) to generate a
   Makefile, and  may generate a config.h file if you ask it to do so. It
   will also make  sure that the results of what it found are available
   in the form of  defines at compile-time, so you can do the
        #if HAVE_PRINTF
        printf("Hello, world!\n");
        #endif
   thing.

   HTH

   rlc

   On Wed, 16 Apr 2003 address@hidden wrote:

   > I've spent a lot of time reading Autotools docs
   > and just wanted to verify something before I get
   > lost in the info overload.....
   >
   > In general,
   > the way to write portable and _flexible_ C code is to have
   > preprocessor directives like:
   >
   > #ifdef STDIO_H_IS_AVAILABLE
   >    printf("Hello world.n");
   > #endif
   >
   > .... and the way those variables
   > get defined is to include config.h which is built by configure
   > script which is built by Autoconf right?
   >
   > In a nutshell, one should not be intimidated by Autoconf
   > because it does not do anything more profound or deep
   > than just make a bunch of #define's right???
   >
   > ...
   >
   > (The reason this was not obvious is because I read that
   > one can run arbitrary shell code with Autoconf/configure
   > system.  This implies Autoconf can do more than I thought
   > and so I got confused.)
   >
   > **What else would you use
   > Autoconf for other than making a list of #defines*?
   >
   > Thanks,
   >
   > Chris
   >
   >
   >
   >