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NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | CONFORMING TO | EXAMPLE | SEE ALSO | COLOPHON |
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ERR(3) Linux Programmer's Manual ERR(3)
err, verr, errx, verrx, warn, vwarn, warnx, vwarnx - formatted error
messages
#include <err.h>
void err(int eval, const char *fmt, ...);
void errx(int eval, const char *fmt, ...);
void warn(const char *fmt, ...);
void warnx(const char *fmt, ...);
#include <stdarg.h>
void verr(int eval, 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 vwarnx(const char *fmt, va_list args);
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.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────┬───────────────┬────────────────┐
│Interface │ Attribute │ Value │
├──────────────────┼───────────────┼────────────────┤
│err(), errx(), │ Thread safety │ MT-Safe locale │
│warn(), warnx(), │ │ │
│verr(), verrx(), │ │ │
│vwarn(), vwarnx() │ │ │
└──────────────────┴───────────────┴────────────────┘
These functions are nonstandard BSD extensions.
Display the current errno information string and exit:
p = malloc(size);
if (p == NULL)
err(1, NULL);
fd = open(file_name, O_RDONLY, 0);
if (fd == -1)
err(1, "%s", file_name);
Display an error message and exit:
if (tm.tm_hour < START_TIME)
errx(1, "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(1, "%s", block_device);
error(3), exit(3), perror(3), printf(3), strerror(3)
This page is part of release 4.15 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2017-09-15 ERR(3)
Pages that refer to this page: errno(3), error(3), perror(3), strerror(3)
Copyright and license for this manual page
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