1# ===========================================================================
2#    https://www.gnu.org/software/autoconf-archive/ax_prefix_config_h.html
3# ===========================================================================
4#
5# SYNOPSIS
6#
7#   AX_PREFIX_CONFIG_H [(OUTPUT-HEADER [,PREFIX [,ORIG-HEADER]])]
8#
9# DESCRIPTION
10#
11#   Generate an installable config.h.
12#
13#   A package should not normally install its config.h as a system header,
14#   but if it must, this macro can be used to avoid namespace pollution by
15#   making a copy of config.h with a prefix added to all the macro names.
16#
17#   Each "#define SOMEDEF" line of the configuration header has the given
18#   prefix added, in the same case as the first character of the macro name.
19#
20#   Defaults:
21#
22#     OUTPUT-HEADER = $PACKAGE-config.h
23#     PREFIX = $PACKAGE
24#     ORIG-HEADER, from AM_CONFIG_HEADER(config.h)
25#
26#   Your configure.ac script should contain both macros in this order.
27#
28#   Example:
29#
30#     AC_INIT(config.h.in)        # config.h.in as created by "autoheader"
31#     AM_INIT_AUTOMAKE(testpkg, 0.1.1)    # makes #undef VERSION and PACKAGE
32#     AM_CONFIG_HEADER(config.h)          # prep config.h from config.h.in
33#     AX_PREFIX_CONFIG_H(mylib/_config.h) # prep mylib/_config.h from it..
34#     AC_MEMORY_H                         # makes "#undef NEED_MEMORY_H"
35#     AC_C_CONST_H                        # makes "#undef const"
36#     AC_OUTPUT(Makefile)                 # creates the "config.h" now
37#                                         # and also mylib/_config.h
38#
39#   If the argument to AX_PREFIX_CONFIG_H would have been omitted then the
40#   default output file would have been called simply "testpkg-config.h",
41#   but even under the name "mylib/_config.h" it contains prefix-defines
42#   like
43#
44#     #ifndef TESTPKG_VERSION
45#     #define TESTPKG_VERSION "0.1.1"
46#     #endif
47#     #ifndef TESTPKG_NEED_MEMORY_H
48#     #define TESTPKG_NEED_MEMORY_H 1
49#     #endif
50#     #ifndef _testpkg_const
51#     #define _testpkg_const _const
52#     #endif
53#
54#   and this "mylib/_config.h" can be installed along with other header
55#   files, which is most convenient when creating a shared library (that has
56#   some headers) whose functionality depends on features detected at
57#   compile-time. No need to invent some "mylib-confdefs.h.in" manually.
58#
59#   Note that some AC_DEFINEs that end up in the config.h file are actually
60#   self-referential - e.g. AC_C_INLINE, AC_C_CONST, and the AC_TYPE_OFF_T
61#   say that they "will define inline|const|off_t if the system does not do
62#   it by itself". You might want to clean up about these - consider an
63#   extra mylib/conf.h that reads something like:
64#
65#     #include <mylib/_config.h>
66#     #ifndef _testpkg_const
67#     #define _testpkg_const const
68#     #endif
69#
70#   and then start using _testpkg_const in the header files. That is also a
71#   good thing to differentiate whether some library-user has starting to
72#   take up with a different compiler, so perhaps it could read something
73#   like this:
74#
75#     #ifdef _MSC_VER
76#     #include <mylib/_msvc.h>
77#     #else
78#     #include <mylib/_config.h>
79#     #endif
80#     #ifndef _testpkg_const
81#     #define _testpkg_const const
82#     #endif
83#
84# LICENSE
85#
86#   Copyright (c) 2014 Reuben Thomas <rrt@sc3d.org>
87#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
88#   Copyright (c) 2008 Marten Svantesson
89#   Copyright (c) 2008 Gerald Point <Gerald.Point@labri.fr>
90#
91#   This program is free software; you can redistribute it and/or modify it
92#   under the terms of the GNU General Public License as published by the
93#   Free Software Foundation; either version 3 of the License, or (at your
94#   option) any later version.
95#
96#   This program is distributed in the hope that it will be useful, but
97#   WITHOUT ANY WARRANTY; without even the implied warranty of
98#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
99#   Public License for more details.
100#
101#   You should have received a copy of the GNU General Public License along
102#   with this program. If not, see <https://www.gnu.org/licenses/>.
103#
104#   As a special exception, the respective Autoconf Macro's copyright owner
105#   gives unlimited permission to copy, distribute and modify the configure
106#   scripts that are the output of Autoconf when processing the Macro. You
107#   need not follow the terms of the GNU General Public License when using
108#   or distributing such scripts, even though portions of the text of the
109#   Macro appear in them. The GNU General Public License (GPL) does govern
110#   all other use of the material that constitutes the Autoconf Macro.
111#
112#   This special exception to the GPL applies to versions of the Autoconf
113#   Macro released by the Autoconf Archive. When you make and distribute a
114#   modified version of the Autoconf Macro, you may extend this special
115#   exception to the GPL to apply to your modified version as well.
116
117#serial 16
118
119AC_DEFUN([AX_PREFIX_CONFIG_H],[dnl
120AC_PREREQ([2.62])
121AC_BEFORE([AC_CONFIG_HEADERS],[$0])dnl
122AC_CONFIG_COMMANDS(m4_default([$1], [$PACKAGE-config.h]),[dnl
123AS_VAR_PUSHDEF([_OUT],[ac_prefix_conf_OUT])dnl
124AS_VAR_PUSHDEF([_DEF],[ac_prefix_conf_DEF])dnl
125AS_VAR_PUSHDEF([_PKG],[ac_prefix_conf_PKG])dnl
126AS_VAR_PUSHDEF([_LOW],[ac_prefix_conf_LOW])dnl
127AS_VAR_PUSHDEF([_UPP],[ac_prefix_conf_UPP])dnl
128AS_VAR_PUSHDEF([_INP],[ac_prefix_conf_INP])dnl
129m4_pushdef([_script],[conftest.prefix])dnl
130m4_pushdef([_symbol],[m4_cr_Letters[]m4_cr_digits[]_])dnl
131_OUT=`echo m4_default([$1], [$PACKAGE-config.h])`
132_DEF=`echo _$_OUT | sed -e "y:m4_cr_letters:m4_cr_LETTERS[]:" -e "s/@<:@^m4_cr_Letters@:>@/_/g"`
133_PKG=`echo m4_default([$2], [$PACKAGE])`
134_LOW=`echo _$_PKG | sed -e "y:m4_cr_LETTERS-:m4_cr_letters[]_:"`
135_UPP=`echo $_PKG | sed -e "y:m4_cr_letters-:m4_cr_LETTERS[]_:"  -e "/^@<:@m4_cr_digits@:>@/s/^/_/"`
136_INP=`echo "$3" | sed -e 's/ *//'`
137if test ".$_INP" = "."; then
138   for ac_file in : $CONFIG_HEADERS; do test "_$ac_file" = _: && continue
139     case "$ac_file" in
140        *.h) _INP=$ac_file ;;
141        *)
142     esac
143     test ".$_INP" != "." && break
144   done
145fi
146if test ".$_INP" = "."; then
147   case "$_OUT" in
148      */*) _INP=`basename "$_OUT"`
149      ;;
150      *-*) _INP=`echo "$_OUT" | sed -e "s/@<:@_symbol@:>@*-//"`
151      ;;
152      *) _INP=config.h
153      ;;
154   esac
155fi
156if test -z "$_PKG" ; then
157   AC_MSG_ERROR([no prefix for _PREFIX_PKG_CONFIG_H])
158else
159  if test ! -f "$_INP" ; then if test -f "$srcdir/$_INP" ; then
160     _INP="$srcdir/$_INP"
161  fi fi
162  AC_MSG_NOTICE(creating $_OUT - prefix $_UPP for $_INP defines)
163  if test -f $_INP ; then
164    AS_ECHO(["s/^@%:@undef  *\\(@<:@m4_cr_LETTERS[]_@:>@\\)/@%:@undef $_UPP""_\\1/"]) > _script
165    AS_ECHO(["s/^@%:@undef  *\\(@<:@m4_cr_letters@:>@\\)/@%:@undef $_LOW""_\\1/"]) >> _script
166    AS_ECHO(["s/^@%:@def[]ine  *\\(@<:@m4_cr_LETTERS[]_@:>@@<:@_symbol@:>@*\\)\\(.*\\)/@%:@ifndef $_UPP""_\\1\\"]) >> _script
167    AS_ECHO(["@%:@def[]ine $_UPP""_\\1\\2\\"]) >> _script
168    AS_ECHO(["@%:@endif/"]) >> _script
169    AS_ECHO(["s/^@%:@def[]ine  *\\(@<:@m4_cr_letters@:>@@<:@_symbol@:>@*\\)\\(.*\\)/@%:@ifndef $_LOW""_\\1\\"]) >> _script
170    AS_ECHO(["@%:@define $_LOW""_\\1\\2\\"]) >> _script
171    AS_ECHO(["@%:@endif/"]) >> _script
172    # now executing _script on _DEF input to create _OUT output file
173    echo "@%:@ifndef $_DEF"      >$tmp/pconfig.h
174    echo "@%:@def[]ine $_DEF 1" >>$tmp/pconfig.h
175    echo ' ' >>$tmp/pconfig.h
176    echo /'*' $_OUT. Generated automatically at end of configure. '*'/ >>$tmp/pconfig.h
177
178    sed -f _script $_INP >>$tmp/pconfig.h
179    echo ' ' >>$tmp/pconfig.h
180    echo '/* once:' $_DEF '*/' >>$tmp/pconfig.h
181    echo "@%:@endif" >>$tmp/pconfig.h
182    if cmp -s $_OUT $tmp/pconfig.h 2>/dev/null; then
183      AC_MSG_NOTICE([$_OUT is unchanged])
184    else
185      ac_dir=`AS_DIRNAME(["$_OUT"])`
186      AS_MKDIR_P(["$ac_dir"])
187      rm -f "$_OUT"
188      mv $tmp/pconfig.h "$_OUT"
189    fi
190  else
191    AC_MSG_ERROR([input file $_INP does not exist - skip generating $_OUT])
192  fi
193  rm -f conftest.*
194fi
195m4_popdef([_symbol])dnl
196m4_popdef([_script])dnl
197AS_VAR_POPDEF([_INP])dnl
198AS_VAR_POPDEF([_UPP])dnl
199AS_VAR_POPDEF([_LOW])dnl
200AS_VAR_POPDEF([_PKG])dnl
201AS_VAR_POPDEF([_DEF])dnl
202AS_VAR_POPDEF([_OUT])dnl
203],[PACKAGE="$PACKAGE"])])
204