unix编程书中的 ourhdr.h代码

真心不知到里面写的具体什么意思，先记下吧。

 /*Our own header, to be included after  all standard system headers*/
 #ifndef __ourhdr_h
 #define __ourhdr_h

 #include    <errno.h>               /*for definition of errno                      */
 #include    <stdarg.h>              /*ANSI C header file                           */
 #include    <sys/types.h>           /* required for some of our prototypes         */
 #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                             */
 #define FILE_MODE       (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
                                         /* default file access permissions for new files */
 #define DIR_MODE        (FILE_MODE | S_IXUSR | S_IXGRP | S_IXOTH)
                                         /* default permissions for new directoris */
 typedef void    Sigfunc(int);   /* for signal handlers */
                                         /* 4.3BSD Reno <signal.h> doesn't define
 SIG_ERR */
 #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} */
 int      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} */
 ssize_t  writen(int, const void *, size_t);     /* {Prog writen} */
 int              daemon_init(void);                     /* {Prog daemoninit} */
 int              s_pipe(int *);                         /* {Progs svr4_spipe bsd spipe} */
 int              recv_fd(int, ssize_t (*func)(int, const void *, size_t));
                                                         /* {Prog recvfd_svr4 recvfd_43bsd} */

 int              send_fd(int, int);                     /* {Progs sendfd_svr4 se
 dfd_43bsd} */
 int              send_err(int, int, const char *);/* {Prog senderr} */
 int              serv_listen(const char *);     /* {Progs servlisten_svr4 servli
 ten_4
 4bsd} */
 int              serv_accept(int, uid_t *);     /* {Progs servaccept_svr4 servac
 ept_4
 4bsd} */
 int              cli_conn(const char *);        /* {Progs cliconn_svr4 cliconn_4
 bsd} */
 int              buf_args(char *, int (*func)(int, char **));
                                                 /* {Prog bufargs} */
 int              ptym_open(char *);                     /* {Progs ptyopen_svr4 p yopen_44bsd} */
 int              ptys_open(int, char *);        /* {Progs ptyopen_svr4 ptyopen_4 bsd} */

 #ifdef  TIOCGWINSZ
 pid_t    pty_fork(int *, char *, 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_readlock(fd, offset, whence, len)  lock_test(fd, F_RDLCK, offset, whence, len)
 #define is_writelock(fd, offset, whence, len) lock_test(fd, F_WRLCK, offset, whence, len)
 void    err_dump(const char *, ...);    /* {App misc_source} */
 void    err_msg(const char *, ...);
 void    err_quit(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_condition  } */
 void    TELL_PARENT(pid_t);
 void    TELL_CHILD(pid_t);
 void    WAIT_PARENT(void);
 void    WAIT_CHILD(void);
 #endif  /* __ourhdr_h */

 static void err_doit(int, const char*, va_list);
 char *pname = NULL; /* caller can set this from argv[0]*/
 /* Nonfatal error realated to a system call . print a message and return . */
 void err_ret(const char *fmt,...)
 {
    va_list ap;
    va_start(ap, fmt);
    err_doit(, fmt, ap);
    va_end(ap);

     return;
 }

 /* 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(, fmt, ap);
    va_end(ap);
    exit();
 }
 /* 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(, fmt, ap);
    va_end(ap);
    abort(); /* dump core and terminate */
    exit(); /* shouldn't get here */
 }

 /* Nofatal error related to a system call . print a message and return. */
 void err_msg(const char *fmt,...)
 {
    va_list ap;

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

    return;
 }
 /* Fatal error related to a system call . print a message and terminate. */
 void err_quit(const char *fmt,...)
 {
    va_list ap;
    va_start(ap, fmt);
    err_doit(, fmt, ap);
    va_end(ap);
    exit();
 }
 /* print a message and return to caller. caller specifies "errnoflag". */
 static void err_doit(int errnoflag, const char *fmt, va_list ap)
 {
    int errno_save;
    char buf[MAXLINE];

    errno_save = errno;  /* value caller might want printed */
    vsprintf(buf, fmt, ap);

    if (errnoflag)
      sprintf(buf+strlen(buf),": %s", strerror(errno_save));

    strcat(buf, "\n");
    fflush(stdout); /* in case stdout and stderr are the same */
    fputs(buf, stderr);
    fflush(NULL); /*flushes and stdio  output streams */

    return;
 }