在查看unix高级编程中的代码时,如果我们编写书中的代码,发现一般都会报错,这是因为作者在写这本书时,他自己编写了一个头文件,跟一个差错处理文件,出来处理他自己的代码错误信息;
下面我们来看下代码的内容:
我实现第一个代码,关于文件的打开,实现 ls 命令的代码;
#include "apue.h"
#include <stdio.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("cat‘t open %s",argv[1]);
}
while( ( dirp = readdir(dp) ) != NULL )
{
printf("%s\n",dirp -> d_name);
}
closedir(dp);
exit(0);
}
编译:
[email protected]:/home/aiyq195/lx/unixc/1# vi myls.c
[email protected]:/home/aiyq195/lx/unixc/1# gcc myls.c -o myls
myls.c:1:18: 致命错误: apue.h:没有那个文件或目录
编译中断。
执行后,发现文件内的头文件apue.h 没有;需要网上查找到文件,然后将文件的放入到usr/include 文件中;
下面的内容是缺少的头文件的内容 :apue.h
/* Our own header, to be included before all standard system headers */
#ifndef _APUE_H
#define _APUE_H
#if defined(SOLARIS)
#define _XOPEN_SOURCE 500 /* Single UNIX Specification, Version 2 for Solaris 9 */
#define CMSG_LEN(x) _CMSG_DATA_ALIGN(sizeof(struct cmsghdr)+(x))
#elif !defined(BSD)
#define _XOPEN_SOURCE 600 /* Single UNIX Specification, Version 3 */
#endif
#include <sys/types.h> /* some systems still require this */
#include <sys/stat.h>
#include <sys/termios.h> /* for winsize */
#ifndef TIOCGWINSZ
#include <sys/ioctl.h>
#endif
#include <stdio.h> /* for convenience */
#include <stdlib.h> /* for convenience */
#include <stddef.h> /* for offsetof */
#include <string.h> /* for convenience */
#include <unistd.h> /* for convenience */
#include <signal.h> /* for SIG_ERR */
#define MAXLINE 4096 /* max line length */
/*
* Default file access permissions for new files.
*/
#define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
/*
* Default permissions for new directories.
*/
#define DIR_MODE (FILE_MODE | S_IXUSR | S_IXGRP | S_IXOTH)
typedef void Sigfunc(int); /* for signal handlers */
#if defined(SIG_IGN) && !defined(SIG_ERR)
#define SIG_ERR ((Sigfunc *)-1)
#endif
#define min(a,b) ((a) < (b) ? (a) : (b))
#define max(a,b) ((a) > (b) ? (a) : (b))
/*
* Prototypes for our own functions.
*/
char *path_alloc(int *); /* {Prog pathalloc} */
long open_max(void); /* {Prog openmax} */
void clr_fl(int, int); /* {Prog setfl} */
void set_fl(int, int); /* {Prog setfl} */
void pr_exit(int); /* {Prog prexit} */
void pr_mask(const char *); /* {Prog prmask} */
Sigfunc *signal_intr(int, Sigfunc *); /* {Prog signal_intr_function} */
int tty_cbreak(int); /* {Prog raw} */
int tty_raw(int); /* {Prog raw} */
int tty_reset(int); /* {Prog raw} */
void tty_atexit(void); /* {Prog raw} */
#ifdef ECHO /* only if <termios.h> has been included */
struct termios *tty_termios(void); /* {Prog raw} */
#endif
void sleep_us(unsigned int); /* {Ex sleepus} */
ssize_t readn(int, void *, size_t); /* {Prog readn_writen} */
ssize_t writen(int, const void *, size_t); /* {Prog readn_writen} */
void daemonize(const char *); /* {Prog daemoninit} */
int s_pipe(int *); /* {Progs streams_spipe sock_spipe} */
int recv_fd(int, ssize_t (*func)(int,
const void *, size_t));/* {Progs recvfd_streams recvfd_sockets} */
int send_fd(int, int); /* {Progs sendfd_streams sendfd_sockets} */
int send_err(int, int,
const char *); /* {Prog senderr} */
int serv_listen(const char *); /* {Progs servlisten_streams servlisten_sockets} */
int serv_accept(int, uid_t *); /* {Progs servaccept_streams servaccept_sockets} */
int cli_conn(const char *); /* {Progs cliconn_streams cliconn_sockets} */
int buf_args(char *, int (*func)(int,
char **)); /* {Prog bufargs} */
int ptym_open(char *, int); /* {Progs3 ptyopen_streams ptyopen_bsd ptyopen_linux} */
int ptys_open(char *); /* {Progs3 ptyopen_streams ptyopen_bsd ptyopen_linux} */
#ifdef TIOCGWINSZ
pid_t pty_fork(int *, char *, int, const struct termios *,
const struct winsize *); /* {Prog ptyfork} */
#endif
int lock_reg(int, int, int, off_t, int, off_t); /* {Prog lockreg} */
#define read_lock(fd, offset, whence, len) \
lock_reg((fd), F_SETLK, F_RDLCK, (offset), (whence), (len))
#define readw_lock(fd, offset, whence, len) \
lock_reg((fd), F_SETLKW, F_RDLCK, (offset), (whence), (len))
#define write_lock(fd, offset, whence, len) \
lock_reg((fd), F_SETLK, F_WRLCK, (offset), (whence), (len))
#define writew_lock(fd, offset, whence, len) \
lock_reg((fd), F_SETLKW, F_WRLCK, (offset), (whence), (len))
#define un_lock(fd, offset, whence, len) \
lock_reg((fd), F_SETLK, F_UNLCK, (offset), (whence), (len))
pid_t lock_test(int, int, off_t, int, off_t); /* {Prog locktest} */
#define is_read_lockable(fd, offset, whence, len) \
(lock_test((fd), F_RDLCK, (offset), (whence), (len)) == 0)
#define is_write_lockable(fd, offset, whence, len) \
(lock_test((fd), F_WRLCK, (offset), (whence), (len)) == 0)
void err_dump(const char *, ...); /* {App misc_source} */
void err_msg(const char *, ...);
void err_quit(const char *, ...);
void err_exit(int, const char *, ...);
void err_ret(const char *, ...);
void err_sys(const char *, ...);
void log_msg(const char *, ...); /* {App misc_source} */
void log_open(const char *, int, int);
void log_quit(const char *, ...);
void log_ret(const char *, ...);
void log_sys(const char *, ...);
void TELL_WAIT(void); /* parent/child from {Sec race_conditions} */
void TELL_PARENT(pid_t);
void TELL_CHILD(pid_t);
void WAIT_PARENT(void);
void WAIT_CHILD(void);
#endif /* _APUE_H */
[email protected]:/home/aiyq195/lx/unixc/1# gcc myls.c -o myls
/tmp/ccsk0VJv.o:在函数‘main’中:
myls.c:(.text+0x17):对‘err_quit’未定义的引用
myls.c:(.text+0x4a):对‘err_sys’未定义的引用
collect2: 错误: ld 返回 1
再次编译后,又发现.c文件的函数不存在,所以,需要再次将包含这些函数的文件找到;
查找到,该文件又是一个作者自己写的差错处理文件- error.c;
将该文件找到,放入到你的代码下;
然后将error.c 的文件放入到该路径下:
[email protected]:/home/aiyq195/lx/unixc/1# ls
error.c myls.c
[email protected]:/home/aiyq195/lx/unixc/1# gcc -o myls myls.c [email protected]:/home/aiyq195/lx/unixc/1# ls
error.c myls myls.c
[email protected]:/home/aiyq195/lx/unixc/1# ./myls ./
myls
.
myls.c
..
error.c