unix网络编程源码和头文件的使用

1.编译《UNP》


我们首先产生一个目录，以后自己的代码就敲在这个目录里。
mkdir /home/hehe/study/unp

仍然是下载到/home/hehe/download/，解压缩，进入目录
cd /home/hehe/download/unpv13e/
README文件中说的很详细：
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
Execute the following from the src/ directory:

    ./configure    # try to figure out all implementation differences

    cd lib         # build the basic library that all programs need
    make           # use "gmake" everywhere on BSD/OS systems

    cd ../libfree  # continue building the basic library
    make

    cd ../libroute # only if your system supports 4.4BSD style routing sockets
    make           # only if your system supports 4.4BSD style routing sockets

    cd ../libxti   # only if your system supports XTI
    make           # only if your system supports XTI

    cd ../intro    # build and test a basic client program
    make daytimetcpcli
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
这里只编译lib下的文件，这样可以产生libunp.a，复制这个静态库到/usr/lib/和/usr/lib64/
如果提示：
unp.h:139: error: conflicting types for ‘socklen_t’
/usr/include/bits/socket.h:35: error: previous declaration of ‘socklen_t’ was here
需要注释掉当前目录中unp.h的第１３９行。
复制libunp.a到系统目录：
root@dan-laptop:/home/hehe/download/unpv13e/lib# cp ../libunp.a /usr/lib
root@dan-laptop:/home/hehe/download/unpv13e/lib# cp ../libunp.a /usr/lib64/

2.使用unp.h和libunp.a
如果直接复制unpv13e/lib/unp.h和config.h到/usr/include，那么在别的目录编译书上代码时，很可会得到类似下面的错误：
In file included from daytimetcpsrv1.c:1:
/usr/include/unp.h:227: error: redefinition of ‘struct sockaddr_storage’
In file included from daytimetcpsrv1.c:1:
/usr/include/unp.h:249:30: error: ../lib/addrinfo.h: No such file or directory
/usr/include/unp.h:263: error: redefinition of ‘struct timespec’
/usr/include/unp.h:363: error: conflicting types for ‘gai_strerror’
/usr/include/netdb.h:647: error: previous declaration of ‘gai_strerror’ was here
/usr/include/unp.h:367: error: conflicting types for ‘getnameinfo’
/usr/include/netdb.h:653: error: previous declaration of ‘getnameinfo’ was here
/usr/include/unp.h:371: error: conflicting types for ‘gethostname’
/usr/include/unistd.h:857: error: previous declaration of ‘gethostname’ was here
/usr/include/unp.h:387: error: conflicting types for ‘inet_ntop’
/usr/include/arpa/inet.h:65: error: previous declaration of ‘inet_ntop’ was here
/usr/include/unp.h:395: error: conflicting types for ‘pselect’
/usr/include/sys/select.h:121: error: previous declaration of ‘pselect’ was here
daytimetcpsrv1.c: In function ‘main’:
daytimetcpsrv1.c:9: error: ‘MAX_LINE’ undeclared (first use in this function)
daytimetcpsrv1.c:9: error: (Each undeclared identifier is reported only once
daytimetcpsrv1.c:9: error: for each function it appears in.)
dan@dan-laptop:~/study/unp/4$ rm -f /usr/include/unp.h

这是因为unp.h包含config.h使用的是#include "../config.h",而此时unp.h和config.h的位置关系发生了变化，只需改为#include "./config.h"即可