err, verr, errx, verrx, warn, vwarn, warnx, vwarnx, - formatted error messages
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.Fd #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 ...
.Fd #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);
error(3), exit(3), printf(3), perror(3), strerror(3)
These functions are non-standard BSD extensions.
The err and warn functions first appeared in BSD 4.4 .
| March 6, 1999 | ERR (3) |