这几天在阅读libevent源码，发现参考资料是基于libevent-2.1的版本，所以就去官网下载了2.1的版本：
http://libevent.org/ （其实是在git下载的：https://github.com/libevent/libevent），版本应该是libevent-2.1.so.5.0.0
下载下来，发现目录里面没有常见的configure, Makefile等文件，搜索之后，了解到需要使用autoconf, automake等工具进行处理。
首先针对automake等工具进行了学习（目录在/home/work/liu_chao/autoMake/）：
先写了些示例代码，分为两个文件：
helloworld.cpp
#include "helloworld.h"
using namespace std;
int main(int argc, char **argv) {
printf("Hello Linux!\n");
return 0;
}
以及helloworld.h
#include <iostream>
autoconf需要configure.ac文件，可以使用autoscan命令先生成configure.scan（错误信息可以先忽略）
[autoMake]$ autoscan autom4te: configure.ac: no such file or directory autoscan: /usr/bin/autom4te failed with exit status: 1 [autoMake]$ ll -rw-rw-r-- 1 work work 0 May 3 17:13 autoscan.log -rw-rw-r-- 1 work work 559 May 3 17:13 configure.scan -rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp -rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h
configure.scan原始内容如下：
# -*- Autoconf -*-
# Process this file with autoconf to produce a configure script.
AC_PREREQ(2.59)
AC_INIT(FULL-PACKAGE-NAME, VERSION, BUG-REPORT-ADDRESS)
AC_CONFIG_SRCDIR([helloworld.cpp])
AC_CONFIG_HEADER([config.h])
# Checks for programs.
AC_PROG_CXX
AC_PROG_CC
# Checks for libraries.
# Checks for header files.
# Checks for typedefs, structures, and compiler characteristics.
# Checks for library functions.
AC_OUTPUT
将configure.scan改名为configure.in（configure.ac亦可），将内容修改如下：
# -*- Autoconf -*- # Process this file with autoconf to produce a configure script. AC_PREREQ(2.59) #AC_INIT(FULL-PACKAGE-NAME, VERSION, BUG-REPORT-ADDRESS) #modified, ignore 3rd parameter email_address AC_INIT(helloworld, 1.0) AC_CONFIG_SRCDIR([helloworld.cpp]) #AC_CONFIG_HEADER([config.h]) #added AM_INIT_AUTOMAKE(helloworld, 1.0) # Checks for programs. AC_PROG_CXX # Checks for libraries. # Checks for header files. # Checks for typedefs, structures, and compiler characteristics. # Checks for library functions. #added AC_CONFIG_FILES([Makefile]) AC_OUTPUT
直接运行autoconf，会有如下报错（但是configure文件仍然生成）
[autoMake]$ autoconf
configure.in:11: error: possibly undefined macro: AM_INIT_AUTOMAKE
If this token and others are legitimate, please use m4_pattern_allow.
See the Autoconf documentation.
[utoMake]$ ll
total 104
drwxr-xr-x 2 work work 4096 May 3 17:26 autom4te.cache
-rw-rw-r-- 1 work work 0 May 3 17:24 autoscan.log
-rwxrwxr-x 1 work work 89791 May 3 17:26 configure
-rw-rw-r-- 1 work work 615 May 3 17:25 configure.in
-rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp
-rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h
这个报错是因为没有运行命令aclocal来生成宏（会生成文件aclocal.m4）。删除刚刚生成的文件，重新运行如下：
[autoMake]$ aclocal [autoMake]$ autoconf [autoMake]$ ll total 176 -rw-rw-r-- 1 work work 38499 May 3 17:29 aclocal.m4 drwxr-xr-x 2 work work 4096 May 3 17:29 autom4te.cache -rw-rw-r-- 1 work work 0 May 3 17:24 autoscan.log -rwxrwxr-x 1 work work 119798 May 3 17:29 configure -rw-rw-r-- 1 work work 615 May 3 17:25 configure.in -rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp -rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h
在下一步automake前，需要新建文件Makefile.am，内容如下：
AUTOMAKE_OPTIONS=foreign bin_PROGRAMS=helloworld helloworld_SOURCES=helloworld.cpp helloworld.h
automake提供了三种软件等级：foreign、gnu和gnits，这里选择foreign，就会只检查必须文件。
再之后运行命令：automake --add-missing（选项--add-missing的定义是“add missing standard files to package”，它会让automake加入一个标准的软件包所必须的一些文件。）
[autoMake]$ automake --add-missing configure.in: installing `./install-sh‘ configure.in: installing `./missing‘ Makefile.am: installing `./depcomp‘ [autoMake]$ ll total 200 -rw-rw-r-- 1 work work 38499 May 3 17:29 aclocal.m4 drwxr-xr-x 2 work work 4096 May 3 18:07 autom4te.cache -rw-rw-r-- 1 work work 0 May 3 17:24 autoscan.log -rwxrwxr-x 1 work work 119798 May 3 17:29 configure -rw-rw-r-- 1 work work 616 May 3 18:07 configure.in lrwxrwxrwx 1 work work 31 May 3 18:08 depcomp -> /usr/share/automake-1.9/depcomp -rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp -rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h lrwxrwxrwx 1 work work 34 May 3 18:08 install-sh -> /usr/share/automake-1.9/install-sh -rw-rw-r-- 1 work work 96 May 3 17:35 Makefile.am -rw-rw-r-- 1 work work 16964 May 3 18:08 Makefile.in lrwxrwxrwx 1 work work 31 May 3 18:08 missing -> /usr/share/automake-1.9/missing
可以发现，Makefile.in文件被生成了。再之后，就可以用configure命令了：
[autoMake]$ ./configure checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for gawk... gawk checking whether make sets $(MAKE)... yes checking for g++... g++ checking for C++ compiler default output file name... a.out checking whether the C++ compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking for style of include used by make... GNU checking dependency style of g++... gcc3 configure: creating ./config.status config.status: creating Makefile config.status: creating config.h config.status: error: cannot find input file: config.h.in
可以看到Makefile文件被生成：
[autoMake]$ ll total 268 -rw-rw-r-- 1 work work 38499 May 3 17:29 aclocal.m4 drwxr-xr-x 2 work work 4096 May 3 18:07 autom4te.cache -rw-rw-r-- 1 work work 0 May 3 17:24 autoscan.log -rw-rw-r-- 1 work work 8360 May 3 18:09 config.log -rwxrwxr-x 1 work work 35215 May 3 18:09 config.status -rwxrwxr-x 1 work work 119798 May 3 17:29 configure -rw-rw-r-- 1 work work 616 May 3 18:07 configure.in lrwxrwxrwx 1 work work 31 May 3 18:08 depcomp -> /usr/share/automake-1.9/depcomp -rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp -rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h lrwxrwxrwx 1 work work 34 May 3 18:08 install-sh -> /usr/share/automake-1.9/install-sh -rw-rw-r-- 1 work work 16660 May 3 18:09 Makefile -rw-rw-r-- 1 work work 96 May 3 17:35 Makefile.am -rw-rw-r-- 1 work work 16964 May 3 18:08 Makefile.in lrwxrwxrwx 1 work work 31 May 3 18:08 missing -> /usr/share/automake-1.9/missing
再之后，通过make，就能生成可执行文件：
[autoMake]$ make cd . && /bin/sh /home/work/liu_chao/autoMake/missing --run aclocal-1.9 cd . && /bin/sh /home/work/liu_chao/autoMake/missing --run automake-1.9 --foreign cd . && /bin/sh /home/work/liu_chao/autoMake/missing --run autoconf /bin/sh ./config.status --recheck running /bin/sh ./configure --no-create --no-recursion checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for gawk... gawk checking whether make sets $(MAKE)... yes checking for g++... g++ checking for C++ compiler default output file name... a.out checking whether the C++ compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking for style of include used by make... GNU checking dependency style of g++... gcc3 configure: creating ./config.status /bin/sh ./config.status config.status: creating Makefile config.status: executing depfiles commands if g++ -DPACKAGE_NAME=\"helloworld\" -DPACKAGE_TARNAME=\"helloworld\" -DPACKAGE_VERSION=\"1.0\" -DPACKAGE_STRING=\"helloworld\ 1.0\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"helloworld\" -DVERSION=\"1.0\" -I. -I. -g -O2 -MT helloworld.o -MD -MP -MF ".deps/helloworld.Tpo" -c -o helloworld.o helloworld.cpp; \ then mv -f ".deps/helloworld.Tpo" ".deps/helloworld.Po"; else rm -f ".deps/helloworld.Tpo"; exit 1; fi g++ -g -O2 -o helloworld helloworld.o [autoMake]$ ll total 404 -rw-rw-r-- 1 work work 38499 May 3 18:10 aclocal.m4 drwxr-xr-x 2 work work 4096 May 3 18:10 autom4te.cache -rw-rw-r-- 1 work work 0 May 3 17:24 autoscan.log -rw-rw-r-- 1 work work 8513 May 3 18:10 config.log -rwxrwxr-x 1 work work 28906 May 3 18:10 config.status -rwxrwxr-x 1 work work 112022 May 3 18:10 configure -rw-rw-r-- 1 work work 616 May 3 18:07 configure.in lrwxrwxrwx 1 work work 31 May 3 18:08 depcomp -> /usr/share/automake-1.9/depcomp -rwxrwxr-x 1 work work 57820 May 3 18:10 helloworld -rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp -rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h -rw-rw-r-- 1 work work 87160 May 3 18:10 helloworld.o lrwxrwxrwx 1 work work 34 May 3 18:08 install-sh -> /usr/share/automake-1.9/install-sh -rw-rw-r-- 1 work work 16839 May 3 18:10 Makefile -rw-rw-r-- 1 work work 96 May 3 17:35 Makefile.am -rw-rw-r-- 1 work work 16964 May 3 18:10 Makefile.in lrwxrwxrwx 1 work work 31 May 3 18:08 missing -> /usr/share/automake-1.9/missing
make install是将可执行文件安装到系统目录中。这里不需要这一步。
可以通过make dist来生成安装包：
[autoMake]$ make dist
{ test ! -d helloworld-1.0 || { find helloworld-1.0 -type d ! -perm -200 -exec chmod u+w {} ‘;‘ && rm -fr helloworld-1.0; }; }
mkdir helloworld-1.0
find helloworld-1.0 -type d ! -perm -777 -exec chmod a+rwx {} \; -o ! -type d ! -perm -444 -links 1 -exec chmod a+r {} \; -o ! -type d ! -perm -400 -exec chmod a+r {} \; -o ! -type d ! -perm -444 -exec /bin/sh /home/work/liu_chao/autoMake/install-sh -c -m a+r {} {} \; || chmod -R a+r helloworld-1.0
tardir=helloworld-1.0 && /bin/sh /home/work/liu_chao/autoMake/missing --run tar chof - "$tardir" | GZIP=--best gzip -c >helloworld-1.0.tar.gz
{ test ! -d helloworld-1.0 || { find helloworld-1.0 -type d ! -perm -200 -exec chmod u+w {} ‘;‘ && rm -fr helloworld-1.0; }; }
[autoMake]$ ll
total 460
-rw-rw-r-- 1 work work 38499 May 3 18:10 aclocal.m4
drwxr-xr-x 2 work work 4096 May 3 18:10 autom4te.cache
-rw-rw-r-- 1 work work 0 May 3 17:24 autoscan.log
-rw-rw-r-- 1 work work 8513 May 3 18:10 config.log
-rwxrwxr-x 1 work work 28906 May 3 18:10 config.status
-rwxrwxr-x 1 work work 112022 May 3 18:10 configure
-rw-rw-r-- 1 work work 616 May 3 18:07 configure.in
lrwxrwxrwx 1 work work 31 May 3 18:08 depcomp -> /usr/share/automake-1.9/depcomp
-rwxrwxr-x 1 work work 57820 May 3 18:10 helloworld
-rw-rw-r-- 1 work work 55726 May 3 18:12 helloworld-1.0.tar.gz
-rw-rw-r-- 1 work work 121 May 3 17:13 helloworld.cpp
-rw-rw-r-- 1 work work 20 May 3 17:13 helloworld.h
-rw-rw-r-- 1 work work 87160 May 3 18:10 helloworld.o
lrwxrwxrwx 1 work work 34 May 3 18:08 install-sh -> /usr/share/automake-1.9/install-sh
-rw-rw-r-- 1 work work 16839 May 3 18:10 Makefile
-rw-rw-r-- 1 work work 96 May 3 17:35 Makefile.am
-rw-rw-r-- 1 work work 16964 May 3 18:10 Makefile.in
lrwxrwxrwx 1 work work 31 May 3 18:08 missing -> /usr/share/automake-1.9/missing
可以看到，生成了 helloworld-1.0.tar.gz 这个文件。
到此，autoconf, automake, configure,和make等常用软件编译和安装的方式已经总结完成。
————————
下面进行libevent的编译，使用命令：
aclocal
autoconf
autoheader
automake --add-missing
出现
configure.ac:125: required file `./ltmain.sh‘ not found
搜索之后，使用：
libevent-master]$ libtoolize --version
libtoolize (GNU libtool) 1.5.6
Copyright (C) 2003 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
libevent-master]$ libtoolize --automake --copy --debug --force
然后重新输入命令：
automake --add-missing
发现没有ltmain.sh相关的错误，但是返回码仍然是1，并且无Makefile生成。
——————————————
重新阅读目录自带的README.md，发现：
# 1. BUILDING AND INSTALLATION (In Depth)
## Autoconf
To build libevent, type
$ ./configure && make
(If you got libevent from the git repository, you will
first need to run the included "autogen.sh" script in order to
generate the configure script.)
所以运行autogen.sh命令：
libevent-master]$ sh autogen.sh
autoreconf: Entering directory `.‘
autoreconf: configure.ac: not using Gettext
autoreconf: running: aclocal --force -I m4
autoreconf: configure.ac: tracing
autoreconf: running: libtoolize --copy --force
autoreconf: running: /usr/bin/autoconf --force
autoreconf: running: /usr/bin/autoheader --force
autoreconf: running: automake --add-missing --copy --force-missing
autoreconf: Leaving directory `.‘
最后返回码为0，并且成功生成Makefile.in（最终的Makefile需要通过 ./configure来生成）
再之后就是下面的命令：
./configure （注意，2.1的libevent默认安装在/usr/local/lib里，需要--prefix=/usr让这个库安装到/usr/lib）
make
make install(可能需要root权限)
——————————————————
关于安装目录，查到的资料是，加载动态库的顺序是：
1. 编译的时候加上-Wl,-rpath=目录的选项，就会在目录程序的.dynamic 段包含一个叫DT_RPATH的项，里面有冒号分隔的目录。
2. 先根据LD_LIBRARY_PATH
3. 再看/etc/ld.so.conf
4. 最后依次在 /lib /usr/lib里查找
开始的时候，我没有注意看编译定义的文件，后来看到的确把/usr/local目录包含了进去，看来使用默认目录/usr/local应该也没有问题。
编译的命令可以参考：
g++ -o lserver lserver.cpp -I/usr/local/include -levent -L/usr/local/lib -Wl,-rpath=/usr/local/lib