如何包括与通用Autoconf宏宏？

Question

Background

我管理建设固件和库约半打不同的主板，它们都使用相同的嵌入式处理器。因为所有的板都使用相同的处理器，则可以是显著公共配置（CC，CXX，CPPFLAGS，CFLAGS，CXXFLAGS，LDFLAGS等）和食谱。对于固件，我使用自定义的makefile包括定义所有常见的配置和配方的通用配置文件。为了简化开发人员的计算机上安装库和头，我用使用GNU自动为库。但是，自定义makefile和GNU自动文件之间显著重复的配置，所以我迁移固件升级到GNU Autotools的。

Objective

我希望能有尽可能少的样板越好。一种用于板configure.ac可能看起来像下面这样：

AC_INIT([mppt], [0.1.0])
AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
: ${CC='arm-none-eabi-gcc -specs=nosys.specs'}
AC_PROG_CC
AM_PROG_CC_C_O
AC_CONFIG_FILES([Makefile])
AC_OUTPUT

一种用于图书馆configure.ac可能看起来像下面这样：

AC_INIT([gcc-arm-none-eabi-samples], [4.7+])
AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
: ${CXX='arm-none-eabi-g++ -specs=nosys.specs'}
AC_PROG_CXX
: ${CC='arm-none-eabi-gcc -specs=nosys.specs'}
AM_PROG_AS
m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
AC_PROG_RANLIB
AC_PROG_CXX_C_O
AC_CONFIG_FILES([Makefile])
AC_OUTPUT

有很多这些文件之间的共同配置。我想有一个定义与普通Autoconf宏宏本地include目录中的一个文件：

AC_DEFUN([TIVASDK],
[AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
: ${CC='arm-none-eabi-gcc -specs=nosys.specs'}
AC_PROG_CC
: ${CXX='arm-none-eabi-g++ -specs=nosys.specs'}
AC_PROG_CXX
AM_PROG_AS
m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
AC_PROG_RANLIB
AM_PROG_CC_C_O
AC_PROG_CXX_C_O
AC_CONFIG_FILES([Makefile])])

然后，我希望能够在第一个例子简化为以下几点：

AC_INIT([mppt], [0.1.0])
TIVASDK
AC_OUTPUT

这有很多的，除了简单的优点。如果，例如，MPPT开发者介绍C ++到固件目前完全用C写的，那么他们还是我不会有更新他们configure.ac。如果我要做出改变的工具链，我将只需要更新推到一个存储库，而不是差不多十。

Problem

Autoconf的不理解宏为我所期望的。有几个不同的失效机理。

expanded before it was required

见this answer。

我有我使用的测试骨架项目。它非常简单qa​​zxswpoi指定Makefile.am：

ACLOCAL_AMFLAGS

ACLOCAL_AMFLAGS = -I "$TIVASDK_HOME"/include

noinst_PROGRAMS = skel.axf

skel_axf_SOURCES = \
    src/main.cpp \
    src/abort.cpp

在TIVASDK_HOME定义。

见~/.profile。它this question使用宏：

configure.ac

它

AC_INIT([skel], [0.1.0])
m4_define([TIVASDK_HOME], [esyscmd([printf "$TIVASDK_HOME"])])
AC_CONFIG_MACRO_DIR(TIVASDK_HOME[/include])
TIVASDK
AC_OUTPUT

构建出的树在autogen.sh：

build

运行

#!/bin/sh

autoreconf -vfi .. && \
  ../configure --prefix="$TIVASDK_HOME" --host=arm-none-eabi

产生如下：

autogen.sh

$ ./autogen.sh 
autoreconf: Entering directory `..'
autoreconf: configure.ac: not using Gettext
autoreconf: running: aclocal --force -I /home/matthew/github.gatech.edu/GTSR/tiva-sdk/include
configure.ac:4: warning: AC_REQUIRE: `AC_PROG_CC' was expanded before it was required
configure.ac:4: http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
/home/matthew/github.gatech.edu/GTSR/tiva-sdk/include/tivasdk.m4:1: TIVASDK is expanded from...
configure.ac:4: the top level
configure.ac:4: warning: AC_REQUIRE: `AC_PROG_CC' was expanded before it was required
configure.ac:4: http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
/home/matthew/github.gatech.edu/GTSR/tiva-sdk/include/tivasdk.m4:1: TIVASDK is expanded from...
configure.ac:4: the top level
autoreconf: configure.ac: tracing
configure.ac:4: warning: AC_REQUIRE: `AC_PROG_CC' was expanded before it was required
configure.ac:4: http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
aclocal.m4:1173: TIVASDK is expanded from...
configure.ac:4: the top level
autoreconf: configure.ac: not using Libtool
autoreconf: running: /usr/bin/autoconf --force
configure.ac:4: warning: AC_REQUIRE: `AC_PROG_CC' was expanded before it was required
configure.ac:4: http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
aclocal.m4:1173: TIVASDK is expanded from...
configure.ac:4: the top level
autoreconf: configure.ac: not using Autoheader
autoreconf: running: automake --add-missing --copy --force-missing
configure.ac:4: warning: AC_REQUIRE: `AC_PROG_CC' was expanded before it was required
configure.ac:4: http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
aclocal.m4:1173: TIVASDK is expanded from...
configure.ac:4: the top level
configure.ac:4: installing './compile'
configure.ac:4: installing './install-sh'
configure.ac:4: installing './missing'
Makefile.am: installing './depcomp'
autoreconf: Leaving directory `..'
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for arm-none-eabi-strip... arm-none-eabi-strip
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking for style of include used by make... GNU
checking for arm-none-eabi-gcc... arm-none-eabi-gcc
checking whether we are using the GNU C compiler... no
checking whether arm-none-eabi-gcc accepts -g... no
checking for arm-none-eabi-gcc option to accept ISO C89... unsupported
checking whether arm-none-eabi-gcc understands -c and -o together... yes
checking dependency style of arm-none-eabi-gcc... gcc3
checking for arm-none-eabi-gcc... (cached) arm-none-eabi-gcc
checking whether the C compiler works... no
configure: error: in `/home/matthew/gatech.edu/sp2019/vip4602/tmp/skel/build':
configure: error: C compiler cannot create executables
See `config.log' for more details

我有command not found扩大一些Autoconf宏出于某种原因预感。我替换AC_DEFUN的AC_DEFUN：

m4_define

运行

m4_define([TIVASDK],
[AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
: ${CC='arm-none-eabi-gcc -specs=nosys.specs'}
AC_PROG_CC
: ${CXX='arm-none-eabi-g++ -specs=nosys.specs'}
AC_PROG_CXX
AM_PROG_AS
AM_PROG_CC_C_O
AC_PROG_CXX_C_O
AC_CONFIG_FILES([Makefile])])

产生如下：

autogen.sh

看来，

$ ./autogen.sh 
autoreconf: Entering directory `..'
autoreconf: configure.ac: not using Gettext
autoreconf: running: aclocal --force -I /home/matthew/github.gatech.edu/GTSR/tiva-sdk/include
autoreconf: configure.ac: tracing
autoreconf: configure.ac: not using Libtool
autoreconf: running: /usr/bin/autoconf --force
autoreconf: configure.ac: not using Autoheader
autoreconf: configure.ac: not using Automake
autoreconf: Leaving directory `..'
../configure: line 1678: TIVASDK: command not found
configure: creating ./config.status

并没有扩张的。我试着用TIVASDK更换m4_define无济于事。

Minimal working example

简单地把在define宏定义修复该问题：

configure.ac

运行

m4_define([TIVASDK],
[AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
: ${CC='arm-none-eabi-gcc -specs=nosys.specs'}
AC_PROG_CC
: ${CXX='arm-none-eabi-g++ -specs=nosys.specs'}
AC_PROG_CXX
AM_PROG_AS
AM_PROG_CC_C_O
AC_PROG_CXX_C_O
AC_CONFIG_FILES([Makefile])])
AC_INIT([skel], [0.1.0])
TIVASDK
AC_OUTPUT

产生如下：

autogen.sh

TL;DR

• 为什么

  $ ./autogen.sh 
  autoreconf: Entering directory `..'
  autoreconf: configure.ac: not using Gettext
  autoreconf: running: aclocal --force -I /home/matthew/github.gatech.edu/GTSR/tiva-sdk/include
  autoreconf: configure.ac: tracing
  autoreconf: configure.ac: not using Libtool
  autoreconf: running: /usr/bin/autoconf --force
  autoreconf: configure.ac: not using Autoheader
  autoreconf: running: automake --add-missing --copy --force-missing
  configure.ac:12: installing './compile'
  configure.ac:12: installing './install-sh'
  configure.ac:12: installing './missing'
  Makefile.am: installing './depcomp'
  autoreconf: Leaving directory `..'
  checking for a BSD-compatible install... /usr/bin/install -c
  checking whether build environment is sane... yes
  checking for arm-none-eabi-strip... arm-none-eabi-strip
  checking for a thread-safe mkdir -p... /bin/mkdir -p
  checking for gawk... gawk
  checking whether make sets $(MAKE)... yes
  checking whether make supports nested variables... yes
  checking for arm-none-eabi-gcc... arm-none-eabi-gcc -specs=nosys.specs
  checking whether the C compiler works... yes
  checking for C compiler default output file name... a.out
  checking for suffix of executables... 
  checking whether we are cross compiling... yes
  checking for suffix of object files... o
  checking whether we are using the GNU C compiler... yes
  checking whether arm-none-eabi-gcc -specs=nosys.specs accepts -g... yes
  checking for arm-none-eabi-gcc -specs=nosys.specs option to accept ISO C89... none needed
  checking whether arm-none-eabi-gcc -specs=nosys.specs understands -c and -o together... yes
  checking for style of include used by make... GNU
  checking dependency style of arm-none-eabi-gcc -specs=nosys.specs... gcc3
  checking whether we are using the GNU C++ compiler... yes
  checking whether arm-none-eabi-g++ -specs=nosys.specs accepts -g... yes
  checking dependency style of arm-none-eabi-g++ -specs=nosys.specs... gcc3
  checking dependency style of arm-none-eabi-gcc -specs=nosys.specs... gcc3
  checking whether arm-none-eabi-g++ -specs=nosys.specs understands -c and -o together... yes
  checking that generated files are newer than configure... done
  configure: creating ./config.status
  config.status: creating Makefile
  config.status: executing depfiles commands

  努力扩大AC_DEFUN？
• 为什么宏定义由AC_PROG_CC似乎不扩大？
• 为什么在m4_define中定义的宏行为不同于在另一个文件中定义，包括宏？

Answer 1

• 为什么AC_DEFUN努力扩大AC_PROG_CC？

我无法解释你的错误的原因。我与你的代码复制，但无法与我最初尝试类似的代码。似乎有多种因素参与，其中两个configure.ac的存在和AC_PROG_CC在一起。

但是，从您最初的尝试，在“问题”的标题上面的问题提出，并从到其错误消息指网上的Autoconf手册页的信息化，我可以通过调用AC_PROG_CXX间接通过AC_PROG_CC根本解决问题而不是直接：

AC_REQUIRE

我发现，顺便说一下，有没有道理，至少在骨架项目，定义或使用

AC_DEFUN([TIVASDK], [
AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
: ${CC='arm-none-eabi-gcc -specs=nosys.specs'}

# HERE:
AC_REQUIRE([AC_PROG_CC])

: ${CXX='arm-none-eabi-g++ -specs=nosys.specs'}
AC_PROG_CXX
# ...

宏。在TIVASDK_HOME定义的ACLOCAL_AMFLAGS显然是不够的。

我不太受使用环境变量来定义所需的宏的位置包括目录的想法迷恋，以及为什么这是非常有用的例子不说清楚我的，但如果你继续与那我鼓励你

• 使用Makefile.in记录该变量，使之珍贵，
• 的确做删除同名的宏。

• 为什么宏定义由m4_define似乎不扩大？

我相信，这将是因为外部宏观文件不能直接使用，而是通过加工来AC_ARG_VAR生成文件aclocal，这是被包括在内。我想你会发现，直接aclocal.m4，出现任何的Autoconf宏定义的范围之外，并没有得到复制。

• 为什么在configure.ac中定义的宏行为不同于在另一个文件中定义，包括宏？

我不认为它。但在m4_define定义的M4宏肯定不会行为不同于其他地方的一个，而不是定义包括在内。