usr/include/sysexits.h

/*
**  SYSEXITS.H -- Exit status codes for system programs.
**
**      This include file attempts to categorize possible error
**      exit statuses for system programs, notably delivermail
**      and the Berkeley network.
**
**      Error numbers begin at EX__BASE to reduce the possibility of
**      clashing with other exit statuses that random programs may
**      already return.  The meaning of the codes is approximately
**      as follows:
**
**      EX_USAGE -- The command was used incorrectly, e.g., with
**              the wrong number of arguments, a bad flag, a bad
**              syntax in a parameter, or whatever.
**      EX_DATAERR -- The input data was incorrect in some way.
**              This should only be used for user's data & not
**              system files.
**      EX_NOINPUT -- An input file (not a system file) did not
**              exist or was not readable.  This could also include
**              errors like "No message" to a mailer (if it cared
**              to catch it).
**      EX_NOUSER -- The user specified did not exist.  This might
**              be used for mail addresses or remote logins.
**      EX_NOHOST -- The host specified did not exist.  This is used
**              in mail addresses or network requests.
**      EX_UNAVAILABLE -- A service is unavailable.  This can occur
**              if a support program or file does not exist.  This
**              can also be used as a catchall message when something
**              you wanted to do doesn't work, but you don't know
**              why.
**      EX_SOFTWARE -- An internal software error has been detected.
**              This should be limited to non-operating system related
**              errors as possible.
**      EX_OSERR -- An operating system error has been detected.
**              This is intended to be used for such things as "cannot
**              fork", "cannot create pipe", or the like.  It includes
**              things like getuid returning a user that does not
**              exist in the passwd file.
**      EX_OSFILE -- Some system file (e.g., /etc/passwd, /etc/utmp,
**              etc.) does not exist, cannot be opened, or has some
**              sort of error (e.g., syntax error).
**      EX_CANTCREAT -- A (user specified) output file cannot be
**              created.
**      EX_IOERR -- An error occurred while doing I/O on some file.
*/

# define EX_OK          0       /* successful termination */

# define EX__BASE       64      /* base value for error messages */

# define EX_USAGE       64      /* command line usage error */
# define EX_DATAERR     65      /* data format error */
# define EX_NOINPUT     66      /* cannot open input */
# define EX_NOUSER      67      /* addressee unknown */
# define EX_NOHOST      68      /* host name unknown */
# define EX_UNAVAILABLE 69      /* service unavailable */
# define EX_SOFTWARE    70      /* internal software error */
# define EX_OSERR       71      /* system error (e.g., can't fork) */
# define EX_OSFILE      72      /* critical OS file missing */
# define EX_CANTCREAT   73      /* can't create (user) output file */
# define EX_IOERR       74      /* input/output error */