环境：
$ cat /etc/issue
Ubuntu 12.04.1 LTS \n \l
$ cat /proc/version
Linux version 3.2.0-48-generic (buildd@komainu) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #74-Ubuntu SMP Thu Jun 6 19:43:26 UTC 2013
$ uname -a
Linux ubuntu-server 3.2.0-48-generic #74-Ubuntu SMP Thu Jun 6 19:43:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
下载：
$ git clone https://github.com/maxliaops/Unix-Network-Programming.git
配置：
$ cd Unix-Network-Programming/
$ chmod 755 configure
$ ./configure
主要的工作是检查系统是否有源码编译所依赖的各种资源（系统版本是否匹配、编译器、库文件、头文件以及结构体定义等等）
checking build system type... x86_64-unknown-linux-gnu
checking host system type... x86_64-unknown-linux-gnu
checking for gcc... gcc
checking for C compiler default output... 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 gcc accepts -g... yes
checking for gcc option to accept ANSI C... none needed
checking for ranlib... ranlib
checking for pthread_create in -lpthread... yes
checking for t_open in -lnsl... no
checking for library containing socket... none required
checking for /usr/local/bind/lib/libbind.a... no
checking for /home/liaops/libbind.a... no
checking for /home/liaops/libresolv.a... no
checking for res_init in -lresolv... no
checking for t_open in -lxti... no
checking for /home/liaops/libunp.a... no
checking for /home/liaops/libunpxti.a... no
checking how to run the C preprocessor... gcc -E
checking for egrep... grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/socket.h... yes
checking for sys/time.h... yes
checking for time.h... yes
checking for netinet/in.h... yes
checking for arpa/inet.h... yes
checking for errno.h... yes
checking for fcntl.h... yes
checking for netdb.h... yes
checking for signal.h... yes
checking for stdio.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for sys/stat.h... yes
checking for sys/uio.h... yes
checking for unistd.h... yes
checking for sys/wait.h... yes
checking for sys/un.h... yes
checking for sys/param.h... yes
checking for sys/select.h... yes
checking for sys/sysctl.h... yes
checking for poll.h... yes
checking for sys/event.h... no
checking for strings.h... yes
checking for sys/ioctl.h... yes
checking for sys/filio.h... no
checking for sys/sockio.h... no
checking for pthread.h... yes
checking for net/if_dl.h... no
checking for xti.h... no
checking for xti_inet.h... no
checking for netconfig.h... no
checking for netdir.h... no
checking for stropts.h... yes
checking whether time.h and sys/time.h may both be included... yes
checking if uint8_t defined... yes
checking if int16_t defined... yes
checking if uint16_t defined... yes
checking if int32_t defined... yes
checking if uint32_t defined... yes
checking if size_t defined... yes
checking if ssize_t defined... yes
checking if socklen_t defined... yes
checking if sa_family_t defined... yes
checking if t_scalar_t defined... no
checking if t_uscalar_t defined... yes
checking for struct sockaddr.sa_len... no
checking for struct sockaddr_storage... yes
checking for struct sockaddr_storage.ss_family... yes
checking for struct msghdr.msg_control... yes
checking for struct ifreq.ifr_mtu... yes
checking for getaddrinfo function prototype in netdb.h... yes
checking for getnameinfo function prototype in netdb.h... yes
checking for gethostname function prototype in unistd.h... yes
checking for getrusage function prototype in sys/resource.h... yes
checking for hstrerror function prototype in netdb.h... yes
checking for if_nametoindex function prototype in net/if.h... yes
checking for inet_aton function prototype in arpa/inet.h... yes
checking for inet_pton function prototype in arpa/inet.h... yes
checking for pselect function prototype in sys/select.h... yes
checking for snprintf function prototype in stdio.h... yes
checking for sockatmark function prototype in sys/socket.h... yes
checking for struct addrinfo... yes
checking for struct if_nameindex... yes
checking for struct sockaddr_dl... no
checking for struct timespec... yes
checking for /dev/tcp... no
checking for /dev/xti/tcp... no
checking for /dev/streams/xtiso/tcp... no
checking for bzero... yes
checking for getaddrinfo... yes
checking for gethostname... yes
checking for gethostbyname2... yes
checking for gethostbyname_r... yes
checking for getnameinfo... yes
checking for hstrerror... yes
checking for if_nametoindex... yes
checking for inet_aton... yes
checking for inet_pton... yes
checking for inet6_rth_init... yes
checking for kqueue... no
checking for kevent... no
checking for mkstemp... yes
checking for poll... yes
checking for pselect... yes
checking for snprintf... yes
checking for sockatmark... yes
checking for vsnprintf... yes
checking for IPv4 support... yes
checking for IPv6 support... yes
checking for Unix domain sockets... yes
checking for multicast support... yes
checking for -I/home/liaops/doc/unp2ev1/src/include... no
configure: creating ./config.status
config.status: creating Makefile
config.status: creating Make.defines
config.status: creating config.h
编译库：
编译所有例程都需要用到的基础库
$ cd lib
$ make
得到静态库文件：libudp.a
查看符号表 （主要是想看一下这个库的各个源文件调用了哪些Linux系统调用）
$ nm -g libunp.a
从中可以发现以下几个文件比较重要，主要是对常用的API进行了一层包装。
wrapsock.o: 对套接字socket的包装
accept
bind
connect
err_quit
err_sys
getenv
getpeername
getsockname
getsockopt
inet6_rth_add
inet6_rth_getaddr
inet6_rth_init
inet6_rth_reverse
inet6_rth_segments
inet6_rth_space
listen
poll
recv
recvfrom
recvmsg
select
send
sendmsg
sendto
setsockopt
shutdown
sockatmark
socket
socketpair
strtol
wrapstdio.o: 对标准IO库中文件相关函数的包装
fclose
fdopen
ferror
fgets
fopen
fputs
wrappthread.o: 对线程库pthread的包装
pthread_cond_broadcast
pthread_cond_signal
pthread_cond_timedwait
pthread_cond_wait
pthread_create
pthread_detach
pthread_join
pthread_key_create
pthread_kill
pthread_mutex_init
pthread_mutex_lock
pthread_mutex_unlock
pthread_mutexattr_init
pthread_mutexattr_setpshared
pthread_once
pthread_setspecific
wrapunix.o: 对其他常用Linux/Unix系统调用的包装
__strdup
calloc
close
dup2
err_quit
err_sys
fcntl
fork
gettimeofday
ioctl
malloc
mkstemp
mmap
open
pipe
read
sigaddset
sigdelset
sigemptyset
sigfillset
sigismember
sigpending
sigprocmask
sysconf
sysctl
unlink
wait
waitpid
write
问题：为什么要对这些API接口进行包装，是否多此一举？
继续编译基本库
$ cd ../libfree/
$ make
gcc -I../lib -g -O2 -D_REENTRANT -Wall -c -o in_cksum.o in_cksum.c
gcc -I../lib -g -O2 -D_REENTRANT -Wall -c -o inet_ntop.o inet_ntop.c
inet_ntop.c: In function ‘inet_ntop’:
inet_ntop.c:61: error: argument ‘size’ doesn’t match prototype
/usr/include/arpa/inet.h:65: error: prototype declaration
make: *** [inet_ntop.o] Error 1
出现错误！
Fix:
inet_ntop.c第61行 size_t size ->改成 socklen_t size）
再次编译
$ make
gcc -I../lib -g -O2 -D_REENTRANT -Wall -c -o inet_ntop.o inet_ntop.c
gcc -I../lib -g -O2 -D_REENTRANT -Wall -c -o inet_pton.o inet_pton.c
ar rv ../libunp.a in_cksum.o inet_ntop.o inet_pton.o
a - in_cksum.o
a - inet_ntop.o
a - inet_pton.o
ranlib ../libunp.a
貌似这次编译的内容并到了libunp.a中，没有生成新的库文件。
$ cd ../libgai
$ make
ar rv ../libunp.a
ranlib ../libunp.a
拷贝生成的库文件到系统库目录
$ cd ..
$ sudo cp libunp.a /usr/lib
$ sudo cp libunp.a /usr/lib32
以后编译代码的时候加上-lunp链接我们的库。
修改unp.h并将其和config.h拷贝到/usr/include中
编译并测试一个基本的客户端例程
$ cd intro/
$ make daytimetcpcli
gcc -I../lib -g -O2 -D_REENTRANT -Wall -c -o daytimetcpcli.o daytimetcpcli.c
gcc -I../lib -g -O2 -D_REENTRANT -Wall -o daytimetcpcli daytimetcpcli.o ../libunp.a -lpthread
编译成功后，在当前目录会生成可执行镜像daytimetcpcli
运行daytimetcpcli
$ ./daytimetcpcli
usage: a.out <IPaddress>
$ ./daytimetcpcli 127.0.0.1
connect error: Connection refused
Fix:
开启daytime服务
$ make daytimetcpsrv
gcc -I../lib -g -O2 -D_REENTRANT -Wall -c -o daytimetcpsrv.o daytimetcpsrv.c
gcc -I../lib -g -O2 -D_REENTRANT -Wall -o daytimetcpsrv daytimetcpsrv.o ../libunp.a -lpthread
sudo ./daytimetcpsrv &
再次运行daytimetcpcli
$ ./daytimetcpcli 127.0.0.1
Mon Mar 3 22:47:35 2014