APUE中第一章实例ls命令的实现中出现错误解决办法

当你跟着书籍上的代码一步一步的敲入并执行后会发现以下错误:

该错误出现的原因是头文件中的  err_quit 函数和 err_sys函数并未实现只有函数声明而已,因此这时只需要我们去 apue.h 头文件中添加上这些函数的具体实现即可.

以下是头文件中的具体实现:

/*
 * Our own header, to be included before all standard system headers.
 */
#ifndef	_APUE_H
#define	_APUE_H

#define _POSIX_C_SOURCE 200809L

#if defined(SOLARIS)		/* Solaris 10 */
#define _XOPEN_SOURCE 600
#else
#define _XOPEN_SOURCE 700
#endif

#include <sys/types.h>		/* some systems still require this */
#include <sys/stat.h>
#include <sys/termios.h>	/* for winsize */
#if defined(MACOS) || !defined(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 <errno.h>
#include <signal.h>		/* for SIG_ERR */

/* added header file */
#include <stdarg.h>    

#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 */

#define	min(a,b)	((a) < (b) ? (a) : (b))
#define	max(a,b)	((a) > (b) ? (a) : (b))

/*
 * Prototypes for our own functions.
 */
char	*path_alloc(size_t *);				/* {Prog pathalloc} */
long	 open_max(void);					/* {Prog openmax} */

int		 set_cloexec(int);					/* {Prog setfd} */
void	 clr_fl(int, int);
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} */

void	 daemonize(const char *);			/* {Prog daemoninit} */

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} */

int		 fd_pipe(int *);					/* {Prog sock_fdpipe} */
int		 recv_fd(int, ssize_t (*func)(int,
                                      const void *, size_t));	/* {Prog recvfd_sockets} */
int		 send_fd(int, int);					/* {Prog sendfd_sockets} */
int		 send_err(int, int,
                  const char *);			/* {Prog senderr} */
int		 serv_listen(const char *);			/* {Prog servlisten_sockets} */
int		 serv_accept(int, uid_t *);			/* {Prog servaccept_sockets} */
int		 cli_conn(const char *);			/* {Prog cliconn_sockets} */
int		 buf_args(char *, int (*func)(int,
                                      char **));				/* {Prog bufargs} */

int		 tty_cbreak(int);					/* {Prog raw} */
int		 tty_raw(int);						/* {Prog raw} */
int		 tty_reset(int);					/* {Prog raw} */
void	 tty_atexit(void);					/* {Prog raw} */
struct termios	*tty_termios(void);			/* {Prog raw} */

int		 ptym_open(char *, int);			/* {Prog ptyopen} */
int		 ptys_open(char *);					/* {Prog ptyopen} */
#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_msg(const char *, ...);			/* {App misc_source} */
void	err_dump(const char *, ...) __attribute__((noreturn));
void	err_quit(const char *, ...) __attribute__((noreturn));
void	err_cont(int, const char *, ...);
void	err_exit(int, const char *, ...) __attribute__((noreturn));
void	err_ret(const char *, ...);
void	err_sys(const char *, ...) __attribute__((noreturn));

void	log_msg(const char *, ...);			/* {App misc_source} */
void	log_open(const char *, int, int);
void	log_quit(const char *, ...) __attribute__((noreturn));
void	log_ret(const char *, ...);
void	log_sys(const char *, ...) __attribute__((noreturn));
void	log_exit(int, const char *, ...) __attribute__((noreturn));

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);

/* added  implemention of function */
static void err_doit(int , int, const char*, va_list);
void 
err_ret(const char*fmt,...){
    va_list ap;

    va_start(ap,fmt);
    err_doit(1, errno, fmt, ap);
    va_end(ap);
}

void 
err_sys(const char *fmt, ...){
    va_list ap;
    va_start(ap, fmt);
    err_doit(1,errno, fmt,ap);
    va_end(ap);
    exit(1);
}

void  
err_exit(int error, const char *fmt, ...)  
{  
    va_list     ap;  

    va_start(ap, fmt);  
    err_doit(1, error, fmt, ap);  
    va_end(ap);  
    exit(1);  

}  

void  
err_dump(const char *fmt, ...)  
{  
    va_list     ap;  

    va_start(ap, fmt);  
    err_doit(1, errno, fmt, ap);  
    va_end(ap);  
    abort();        /* dump core and terminate */  
    exit(1);        /* shouldn鈥榯 get here */  

}  

void  
err_msg(const char *fmt, ...)  
{  
    va_list     ap;  

    va_start(ap, fmt);  
    err_doit(0, 0, fmt, ap);  
    va_end(ap);  

}  

void  
err_quit(const char *fmt, ...)  
{  
    va_list     ap;  

    va_start(ap, fmt);  
    err_doit(0, 0, fmt, ap);  
    va_end(ap);  
    exit(1);  

}  

static void  
err_doit(int errnoflag, int error, const char *fmt, va_list ap)  
{  
    char    buf[MAXLINE];  
    vsnprintf(buf, MAXLINE, fmt, ap);  
    if (errnoflag)  
        snprintf(buf+strlen(buf), MAXLINE-strlen(buf), ": %s",strerror(error));  
    strcat(buf, " ");  
    fflush(stdout);     /* in case stdout and stderr are the same */  
    fputs(buf, stderr);  
    fflush(NULL);       /* flushes all stdio output streams */  

}

#endif	/* _APUE_H */

通过以上修改之后,书籍中的实例即可编译执行,编译后执行结果如下:

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转载自blog.csdn.net/qq_40073459/article/details/103789913