编译unix环境高级编程第一个例子出错解决

unix环境高级编程第一个例子ls.c:

#include "apue.h"
#include <dirent.h>

int
main(int argc,char *argv[])
{
        DIR     *dp;
        struct dirent   *dirp;

        if(argc != 2)
                err_quit("usage: ls directory_name");

        if((dp = opendir(argv[1])) == NULL)
                err_sys("can't open %s", argv[1]);
        while((dirp = readdir(dp))!=NULL)
                printf("%s\n",dirp->d_name);
        closedir(dp);
        exit(0);
}

编译出错：

[john@localhost apue]$ gcc ls.c

/tmp/cchIn3xL.o: In function `main':
ls.c:(.text+0x17): undefined reference to `err_quit'
ls.c:(.text+0x4a): undefined reference to `err_sys'

发现是找不到err_quit和err_sys，因而把unix环境高级编程源码的lib目录下的error.c拷贝出来和一块儿编译:

[john@localhost apue]$ gcc ls.c error.c

OK，解决了。