#include <sysexits.h>
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.
EX_TEMPFAIL -- temporary failure, indicating something that
is not really an error. In sendmail, this means
that a mailer (e.g.) could not create a connection,
and the request should be reattempted later.
EX_PROTOCOL -- the remote system returned something that
was "not possible" during a protocol exchange.
EX_NOPERM -- You did not have sufficient permission to
perform the operation. This is not intended for
file system problems, which should use NOINPUT or
CANTCREAT, but rather for higher level permissions.