sysexits(3) [netbsd man page]
SYSEXITS(3) BSD Library Functions Manual SYSEXITS(3) NAME
sysexits -- preferable exit codes for programs SYNOPSIS
#include <sysexits.h> DESCRIPTION
It is not a good practice to call exit(3) with arbitrary values to indicate a failure condition when ending a program. In addition to the two standard constants in <stdlib.h>, EXIT_SUCCESS and EXIT_FAILURE, the header <sysexits.h> defines few exit codes that can be used as a parameter to the exit(3) function. By using these constants 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 codes is approximately as follows: EX_USAGE (64) 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 (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 catchall message when something you wanted to do does not work, but you do not know why. EX_SOFTWARE (70) An internal software error has been detected. This should be limited to non-operating system related errors as possi- ble. EX_OSERR (71) 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 (72) Some system file (e.g., /etc/passwd, /var/run/utmp, etc.) 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 (e.g.) 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 parenthesis for easy reference. SEE ALSO
err(3), exit(3), stdlib(3) HISTORY
The <sysexits.h> header appeared somewhere after 4.3BSD. The manual page for it appeared in NetBSD 4.0. AUTHORS
This manual page was written by Jorg Wunsch after the comments in <sysexits.h>. BUGS
The choice of an appropriate exit value is often ambiguous. BSD
March 25, 2010 BSD
Check Out this Related Man Page
ERR(3) BSD Library Functions Manual ERR(3) NAME
err, verr, errc, verrc, errx, verrx, warn, vwarn, warnc, vwarnc, warnx, vwarnx, err_set_exit, err_set_file -- formatted error messages LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <err.h> void err(int eval, const char *fmt, ...); void err_set_exit(void (*exitf)(int)); void err_set_file(void *vfp); void errc(int eval, int code, const char *fmt, ...); void errx(int eval, const char *fmt, ...); void warn(const char *fmt, ...); void warnc(int code, const char *fmt, ...); void warnx(const char *fmt, ...); #include <stdarg.h> void verr(int eval, const char *fmt, va_list args); void verrc(int eval, int code, const char *fmt, va_list args); void verrx(int eval, const char *fmt, va_list args); void vwarn(const char *fmt, va_list args); void vwarnc(int code, const char *fmt, va_list args); void vwarnx(const char *fmt, va_list args); DESCRIPTION
The err() and warn() family of functions display a formatted error message on the standard error output, or on another file specified using the err_set_file() function. In all cases, the last component of the program name, a colon character, and a space are output. If the fmt argument is not NULL, the printf(3)-like formatted error message is output. The output is terminated by a newline character. The err(), errc(), verr(), verrc(), warn(), warnc(), vwarn(), and vwarnc() functions append an error message obtained from strerror(3) based on a supplied error code value or the global variable errno, preceded by another colon and space unless the fmt argument is NULL. In the case of the errc(), verrc(), warnc(), and vwarnc() functions, the code argument is used to look up the error message. The err(), verr(), warn(), and vwarn() functions use the global variable errno to look up the error message. The errx() and warnx() functions do not append an error message. The err(), verr(), errc(), verrc(), errx(), and verrx() functions do not return, but exit with the value of the argument eval. It is recom- mended that the standard values defined in sysexits(3) be used for the value of eval. The err_set_exit() function can be used to specify a function which is called before exit(3) to perform any necessary cleanup; passing a null function pointer for exitf resets the hook to do nothing. The err_set_file() function sets the output stream used by the other functions. Its vfp argument must be either a pointer to an open stream (possibly already converted to void *) or a null pointer (in which case the output stream is set to standard error). EXAMPLES
Display the current errno information string and exit: if ((p = malloc(size)) == NULL) err(EX_OSERR, NULL); if ((fd = open(file_name, O_RDONLY, 0)) == -1) err(EX_NOINPUT, "%s", file_name); Display an error message and exit: if (tm.tm_hour < START_TIME) errx(EX_DATAERR, "too early, wait until %s", start_time_string); Warn of an error: if ((fd = open(raw_device, O_RDONLY, 0)) == -1) warnx("%s: %s: trying the block device", raw_device, strerror(errno)); if ((fd = open(block_device, O_RDONLY, 0)) == -1) err(EX_OSFILE, "%s", block_device); Warn of an error without using the global variable errno: error = my_function(); /* returns a value from <errno.h> */ if (error != 0) warnc(error, "my_function"); SEE ALSO
exit(3), fmtmsg(3), printf(3), strerror(3), sysexits(3) STANDARDS
The err() and warn() families of functions are BSD extensions. As such they should not be used in truly portable code. Use strerror() or similar functions instead. HISTORY
The err() and warn() functions first appeared in 4.4BSD. The err_set_exit() and err_set_file() functions first appeared in FreeBSD 2.1. The errc() and warnc() functions first appeared in FreeBSD 3.0. BSD
March 29, 2012 BSD