ac_create_prefix_config_h does not only prefix the names, they get
also converted into ifdefs. That was also necessary, since I had
some problems as this prefixed-header might be included multiple
times, as there is not ifdef-once header/footer for the file
itself. That's my solution to the problem, for making the checks
of autoconf available via a generated header that gets defined
through ac_define's. -- guido
Es schrieb Russ Allbery:
>
> Guido Draheim <[EMAIL PROTECTED]> writes:
>
> > I'm doing the same thing, and in fact, all libraries should put their
> > headers with a subdir prefix, sadly not all of them do it, and
> > automake's support for such a style is limited. Anyway, two ways.
>
> > a) I'm using package/_config.h - this even hint the reader that this
> > file is not a normal header (it is generated!) and it does not
> > get confused for the standard config.h file.
> > b) look at the argument of AC_CONFIG_HEADER - you can specify a
> > different output-file, so that you don't need to have the two
> > same-named.
>
> The name isn't the problem.
>
> Suppose that you have two installable libraries that use autoconf, and in
> both of those libraries you need to probe for a few system features, like
> the proper types, and change the headers and prototypes based on that.
> Now suppose you want to write a program that uses both of those libraries.
> If you include both header files, then the separate package config.h files
> will potentially conflict with each other and result in a bunch of
> redefinition errors.
>
> One thing that you can do is recognize that generally your interface only
> depends on a much restricted subset of the things that you probe for
> actual compilation, and therefore you only need to install a stripped down
> version of config.h. For INN, I use the following awk script to generate
> that stripped-down version with only the symbols that the header files
> need to use, and just add new symbols to it as I need them for the API:
>
> #! /bin/sh
>
> ## $Id: mksystem,v 1.1 2001/02/24 07:59:06 rra Exp $
> ##
> ## Create include/inn/system.h from include/config.h.
> ##
> ## include/config.h is generated by autoconf and contains all of the test
> ## results for a platform. Most of these are only used when building INN,
> ## but some of them are needed for various definitions in the header files
> ## for INN's libraries. We want to be able to install those header files
> ## and their prerequisites, but we don't want to define the normal symbols
> ## defined by autoconf since they're too likely to conflict with other
> ## packages.
> ##
> ## This script takes the path to include/config.h as its only argument and
> ## generates a file suitable for being included as <inn/system.h>. It
> ## contains only the autoconf results needed for INN's API, and the symbols
> ## that might conflict with autoconf results in other packages have INN_
> ## prepended.
>
> cat <<EOF
> /* Automatically generated by mksystem from config.h; do not edit. */
>
> /* This header contains information obtained by INN at configure time that
> is needed by INN headers. Autoconf results that may conflict with the
> autoconf results of another package have INN_ prepended to the
> preprocessor symbols. */
>
> #ifndef INN_SYSTEM_H
> #define INN_SYSTEM_H 1
>
> EOF
>
> awk -f - $1 <<'---END-OF-AWK-SCRIPT---'
>
> /^#define HAVE_INTTYPES_H/ { print save $1 " INN_" $2 " " $3 "\n" }
> /^#define HAVE_STDBOOL_H/ { print save $1 " INN_" $2 " " $3 "\n" }
> /^#define HAVE_SYS_BITTYPES_H/ { print save $1 " INN_" $2 " " $3 "\n" }
>
> { save = $0 "\n" }
>
> ---END-OF-AWK-SCRIPT---
>
> cat <<EOF
> #endif /* INN_SYSTEM_H */
> EOF
>
> --
> Russ Allbery ([EMAIL PROTECTED]) <http://www.eyrie.org/~eagle/>
