unix 环境高级编成 apue.h ，apueerror.h的代码

===================apueerror.h=========================================
$ cat apueerror.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 */
}

===================apue.h=========================================
$ cat 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);

#include "apueerror.h"

#endif  /* _APUE_H */