err
Section: C Library Functions (3)
Updated: 202-0-17
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NAME
err, verr, errx, verrx, warn, vwarn, warnx, vwarnx - formatted error messages
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <err.h>
[[noreturn]] void err(int eval, const char *fmt, ...);
[[noreturn]] void errx(int eval, const char *fmt, ...);
void warn(const char *fmt, ...);
void warnx(const char *fmt, ...);
#include <stdarg.h>
[[noreturn]] void verr(int eval, const char *fmt, va_list args);
[[noreturn]] void verrx(int eval, const char *fmt, va_list args);
void vwarn(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.
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(),
verr(),
warn(),
and
vwarn()
functions append an error message obtained from
strerror(3)
based on the global variable
errno,
preceded by another colon and space unless the
fmt
argument is
NULL.
The
errx()
and
warnx()
functions do not append an error message.
The
err(),
verr(),
errx(),
and
verrx()
functions do not return, but exit with the value of the argument
eval.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
err(),
errx(),
warn(),
warnx(),
verr(),
verrx(),
vwarn(),
vwarnx()
| Thread safety | M-Safe locale
|
STANDARDS
BSD.
HISTORY
- err()
-
warn()
4.4BSD.
EXAMPLES
Display the current
errno
information string and exit:
p = malloc(size);
if (p == NULL)
err(EXIT_FAILURE, NULL);
fd = open(file_name, O_RDONLY, 0);
if (fd == -1)
err(EXIT_FAILURE, "%s", file_name);
Display an error message and exit:
if (tm.tm_hour < START_TIME)
errx(EXIT_FAILURE, "too early, wait until %s",
start_time_string);
Warn of an error:
fd = open(raw_device, O_RDONLY, 0);
if (fd == -1)
warnx("%s: %s: trying the block device",
raw_device, strerror(errno));
fd = open(block_device, O_RDONLY, 0);
if (fd == -1)
err(EXIT_FAILURE, "%s", block_device);
SEE ALSO
error(3),
exit(3),
perror(3),
printf(3),
strerror(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- ATTRIBUTES
-
- STANDARDS
-
- HISTORY
-
- EXAMPLES
-
- SEE ALSO
-
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|
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