如上图，由于apue.h是作者自己实现的，所以我们可以去网上拷贝一份
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/stat.h>
#include <sys/termios.h> /* for winsize */
#include <sys/types.h> /* some systems still require this */
#ifndef TIOCGWINSZ
#include <sys/ioctl.h>
#endif
#include <signal.h> /* for SIG_ERR */
#include <stddef.h> /* for offsetof */
#include <stdio.h> /* for convenience */
#include <stdlib.h> /* for convenience */
#include <string.h> /* for convenience */
#include <unistd.h> /* for convenience */
#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 */
执行gcc myls.c -o myls后发现还是会有问题，err_quit()没有定义
那么我们就去找一份对于err_quit定义的.c文件
error.c
#include <errno.h> /* for definition of errno */
#include <stdarg.h> /* ISO C variable aruments */
#include "apue.h"
static void err_doit(int, int, const char*, va_list);
/*
* Nonfatal error related to a system call.
* Print a message and return.
*/
void err_ret(const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
err_doit(1, errno, fmt, ap);
va_end(ap);
}
/*
* Fatal error related to a system call.
* Print a message and terminate.
*/
void err_sys(const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
err_doit(1, errno, fmt, ap);
va_end(ap);
exit(1);
}
/*
* Fatal error unrelated to a system call.
* Error code passed as explict parameter.
* Print a message and terminate.
*/
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);
}
/*
* Fatal error related to a system call.
* Print a message, dump core, and terminate.
*/
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't get here */
}
/*
* Nonfatal error unrelated to a system call.
* Print a message and return.
*/
void err_msg(const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
err_doit(0, 0, fmt, ap);
va_end(ap);
}
/*
* Fatal error unrelated to a system call.
* Print a message and terminate.
*/
void err_quit(const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
err_doit(0, 0, fmt, ap);
va_end(ap);
exit(1);
}
/*
* Print a message and return to caller.
* Caller specifies "errnoflag".
*/
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, "\n");
fflush(stdout); /* in case stdout and stderr are the same */
fputs(buf, stderr);
fflush(NULL); /* flushes all stdio output streams */
}
一个文件目录项包括这些内容。
