Re: How to install "config.h"

[Raja R Harinath <harinath at cs dot umn dot edu>]

Simon Richter <Simon.Richter@phobos.fachschaften.tu-muenchen.de> writes:
> On 27 Oct 2000, Mark Galassi wrote:
> [Installing config.h]
> 
> > But be careful: if any of the C code in the package itself includes
> > <your-package-name/config.h> you might be in for a nasty surprise: if
> > a version is already installed and a user is compiling a new version
> > from source, that user will pick up the installed .h files which will
> 
> Even more evil: These files will contain definitions for PACKAGE and
> VERSION.

And unless the configure.in tests are exactly the same, you'll have
HAVE_* conflicts.

Compare (on Solaris)

  AC_CHECK_LIB(resolv, inet_aton) #define HAVE_RESOLV 1
  AC_CHECK_FUNC(inet_ntoa)        #define HAVE_INET_NTOA

vs.

  AC_CHECK_LIB(resolv, inet_aton, RESOLV_LIB=-lresolv) #define HAVE_RESOLV 1
  AC_CHECK_FUNC(inet_ntoa)                             #undef HAVE_INET_NTOA

(I know, in "reasonable" circumstances, this example won't really
cause problems, even with both config.h being included.)

And, then we have the problem of having anything depending on the
output of config.status going into $prefix rather than $exec_prefix.

- Hari
-- 
Raja R Harinath ------------------------------ harinath@cs.umn.edu
"When all else fails, read the instructions."      -- Cahn's Axiom
"Our policy is, when in doubt, do the right thing."   -- Roy L Ash