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 a code
or the global variable errno,
preceded by another colon and space unless the fmt argument is NULL.
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(), errx(), and verrx() functions do not return, but exit
with the value of the argument eval.
Display the current errno information string and exit:
if ((p = malloc(size)) == NULL) err(1, NULL); if ((fd = open(file_name, O_RDONLY, 0)) == −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:
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(1, "%s", block_device);