一个简单的执行程序的GNU automake自动生成Makefile的方法及案例
在GNU的世界里，存在Automake这样的工具进行自动生成Makefile文件，automake是由Perl语言编写的，必须与GNU autoconf一并使用，具体的生成过程请参看GNU automake的wikipedia中的右下角的图，地址如下：http://en.wikipedia.org/wiki/Automake，由此图可看到使用自动生成Makefile的工具使用的流程，步骤主要如下：
- autoscan
- 修改生成的configure.scan为configure.in
- aclocal
- autoheader
- autoconf
- 创建Makefile.am并进行具体内容的写入
- automake
- automake
- ./configure生成Makefile
- make得到可执行程序
光空说太抽象了，那么来一个简单的例子吧，
0. 创建一个printf("Hello world!\n")的小程序，创建目录hello后创建hello.c，
ufo@ufo:~/hello$ ls
hello.c
那么下一步即可开始automake的工作了，
1、使用autoscan生成configure.scan
ufo@ufo:~/hello$ autoscan
ufo@ufo:~/hello$ ls
autoscan.log configure.scan hello.c
ufo@ufo:~/hello$ aclocal
aclocal: `configure.ac' or `configure.in' is required
2、在上一步中直接执行aclocal时出现以上的提示，那么就要将生成的configure.scan修改为configure.ac或configure.in再进行aclocal的执行；
ufo@ufo:~/hello$ mv configure.scan configure.in
ufo@ufo:~/hello$ ls
autoscan.log configure.in hello.c
3、执行aclocal
ufo@ufo:~/hello$ aclocal
ufo@ufo:~/hello$ ls
autom4te.cache autoscan.log configure.in hello.c
4、执行autoheader
ufo@ufo:~/hello$ ls
autom4te.cache autoscan.log config.h.in configure.in hello.c
5、执行autoconf
ufo@ufo:~/hello$ autoconf
ufo@ufo:~/hello$ ls
autom4te.cache autoscan.log config.h.in configure configure.in hello.c
6、创建Makefile.am
ufo@ufo:~/hello$ vim Makefile.am
ufo@ufo:~/hello$ cat Makefile.am
bin_PROGRAMS=hello
hello_SOURCES=hello.c
关于Makefile.am中的具体内容的意思是说生成的可执行文件的名称为hello,对应的源代码为hello.c。
7、执行automake
ufo@ufo:~/hello$ automake
configure.in: no proper invocation of AM_INIT_AUTOMAKE was found.
configure.in: You should verify that configure.in invokes AM_INIT_AUTOMAKE,
configure.in: that aclocal.m4 is present in the top-level directory,
configure.in: and that aclocal.m4 was recently regenerated (using aclocal).
automake: no `Makefile.am' found for any configure output
automake: Did you forget AC_CONFIG_FILES([Makefile]) in configure.in?
这时出错了，是说configure.in文件中的AM_INIT_AUTOMAKE没有找到，只有修改configure.in
文件后再从第三步进行重新执行，configure.in中的AC_INIT行下添加
AM_INIT_AUTOMAKE(hello,1.0)，格式为AM_INIT_AUTOMAKE(package,version)，再修改AC_OUTPUT为AC_OUTPUT(Makefile)；
修改完configure.in文件后，再次执行2～7;
8、执行automake
ufo@ufo:~/hello$ automake
configure.in:6: required file `./install-sh' not found
configure.in:6: `automake --add-missing' can install `install-sh'
configure.in:6: required file `./missing' not found
configure.in:6: `automake --add-missing' can install `missing'
Makefile.am: required file `./INSTALL' not found
Makefile.am: `automake --add-missing' can install `INSTALL'
Makefile.am: required file `./NEWS' not found
Makefile.am: required file `./README' not found
Makefile.am: required file `./AUTHORS' not found
Makefile.am: required file `./ChangeLog' not found
Makefile.am: required file `./COPYING' not found
Makefile.am: `automake --add-missing' can install `COPYING'
Makefile.am: required file `./depcomp' not found
Makefile.am: `automake --add-missing' can install `depcomp'
按照提示创建缺少的文件,
ufo@ufo:~/hello$ touch NEWS README AUTHORS ChangeLog再执行:
ufo@ufo:~/hello$ automake --add-missing
没有出错的情况下再次执行automake;
ufo@ufo:~/hello$ ls
aclocal.m4 ChangeLog configure.in INSTALL missing
AUTHORS config.h.in COPYING install-sh NEWS
autom4te.cache config.h.in~ depcomp Makefile.am README
autoscan.log configure hello.c Makefile.in
此时已经生成了生成Makefile文件的cinfigure脚本；
9、./configure生成Makefile
ufo@ufo:~/hello$ ls Makefile
Makefile
10、make得到可执行程序
ufo@ufo:~/hello$ make
make all-am
make[1]: 正在进入目录 `/home/ufo/hello'
gcc -DHAVE_CONFIG_H -I. -g -O2 -MT hello.o -MD -MP -MF .deps/hello.Tpo -c -o hello.o hello.c
mv -f .deps/hello.Tpo .deps/hello.Po
gcc -g -O2 -o hello hello.o
make[1]:正在离开目录 `/home/ufo/hello'
ufo@ufo:~/hello$ ls
aclocal.m4 config.h configure hello.c Makefile.am stamp-h1
AUTHORS config.h.in configure.in hello.o Makefile.in
autom4te.cache config.h.in~ COPYING INSTALL missing
autoscan.log config.log depcomp install-sh NEWS
ChangeLog config.status hello Makefile README
ufo@ufo:~/hello$ ./hello
Hello World!
这就是牛X的automake的例子；关于其中的细节日后有空再表了
