sysexits - preferable exit codes for programs
#include <sysexits.h>
According to style(9), it is not good practice to call exit(3) with arbitrary
values to indicate a failure condition when ending a
program. Instead,
the pre-defined exit codes from sysexits should be
used, so the
caller of the process can get a rough estimation about the
failure class
without looking up the source code.
The successful exit is always indicated by a status of 0, or
EX_OK. 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 code is approximately as follows:
EX_USAGE (64) The command was used incorrectly,
e.g., with the
wrong number of arguments, a bad flag,
bad syntax
in a parameter, or whatever.
EX_DATAERR (65) The input data was incorrect in some
way. This
should only be used for user's data
and not system
files.
EX_NOINPUT (66) 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 (67) The user specified did not exist.
This might be
used for mail addresses or remote logins.
EX_NOHOST (68) The host specified did not exist.
This is used in
mail addresses or network requests.
EX_UNAVAILABLE (69) A service is unavailable. This can
occur if a support
program or file does not exist.
This can also
be used as a catch-all message when
something you
wanted to do doesn't work, but you
don't know why.
EX_SOFTWARE (70) An internal software error has been
detected. This
should be limited to non-operating
system related
errors if possible.
EX_OSERR (71) An operating system error has been detected. This
is intended to be used for such things
as ``cannot
fork'', or ``cannot create pipe''. It
includes
things like getuid(2) returning a user
that does
not exist in the passwd file.
EX_OSFILE (72) Some system file (e.g., /etc/passwd,
/var/run/utmp)
does not exist, cannot be opened, or
has some sort
of error (e.g., syntax error).
EX_CANTCREAT (73) A (user specified) output file cannot
be created.
EX_IOERR (74) An error occurred while doing I/O on
some file.
EX_TEMPFAIL (75) Temporary failure, indicating something that is not
really an error. In sendmail, this
means that a
mailer, for example, could not create
a connection,
and the request should be reattempted
later.
EX_PROTOCOL (76) The remote system returned something
that was ``not
possible'' during a protocol exchange.
EX_NOPERM (77) You did not have sufficient permission
to perform
the operation. This is not intended
for file system
problems, which should use
EX_NOINPUT or
EX_CANTCREAT, but rather for higher
level permissions.
EX_CONFIG (78) Something was found in an unconfigured
or misconfigured
state.
The numerical values corresponding to the symbolical ones
are given in
parentheses for easy reference.
exit(3), style(9)
The sysexits file appeared sometime after 4.3BSD.
This man page was written by Joerg Wunsch after the comments
in
<sysexits.h>.
The choice of an appropriate exit value is often ambiguous.
OpenBSD 3.6 March 31, 1996
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