一，配置
apue.h是作者自己写的一个文件，包含了常用的头文件，系统不自带。其中包含了常用的头文件，以及出错处理函数的定义。使用起来确实很方便。
想要使用，还要进行下面操作，完成相关配置.
在http://www.apuebook.com/下载src.tar.gz源代码的压缩包。
1、解压至/home/user/目录下
2、修改 Make.defines.linux中的WKDIR=/home/xxx/apue.2e，为WKDIR=/home/user/apue.2e
3、返回至apue.2e目录下面，修改linux.mk，将里面的nawk全部改为awk，可以使用这个命令 ：%s/nawk/awk/g
4、make
5、将/home/user/apue.2e/include/apue.h和/home/user/apue.2e/lib/error.c复制到/usr/include目录下
二，要拷贝的apue.h和error.c文件如下：（可以直接复制并拷贝到/usr/include下）
apue.h （添加了一行 #include <error.c>）
/* 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);
#include "error.c"
#endif /* _APUE_H */error.c
#include "apue.h"
#include <errno.h> /* for definition of errno */
#include <stdarg.h> /* ISO C variable aruments */
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 */
}三，示例：
#include <stdio.h>
#include <dirent.h>
int main(int argc, char *argv[])
{
DIR *dp;
struct dirent *dirp;
if(argc!=2)
{
printf("Usage: ls directory_name\n");
return -1;
}
if((dp=opendir(argv[1]))==NULL)
printf("can't open %s\n", argv[1]);
while((dirp = readdir(dp))!=NULL)
printf("%s\n", dirp->d_name);
closedir(dp);
return 0;
}