err(3POSIX)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | HISTORY | ATTRIBUTES | SEE ALSO

NAME

err, verr, verrx, warn, vwarn, warnx, vwarnx- formatted error messages

SYNOPSIS

#include <err.h>

void err(int eval, const char * fmt, ...);
void verr(int eval, const char * fmt, va_list args);
void errx(int eval, const char * fmt, ...);
void verrx(int eval, const char * fmt, va_list args);
void warn(const char * fmt, ...);
void vwarn(const char * fmt, va_list args);
void warnx(const char * fmt, ...);
void vwarnx(const char * fmt, va_list args);

DESCRIPTION

The err and warn family of functions display a formatted error message to the standard error output. If the fmt argument is not NULL , the formatted error message, a colon character, and a space are output. In the case of the err , verr , warn , and vwarn functions, the error message string affiliated with the current value of the global variable errno is output. In all cases, the output is followed by a newline character.

The err , verr , errx , and verrx functions do not return, but exit with the value of the argument eval .

EXAMPLES

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)
        warn("%s", block_device);

HISTORY

The err and warn functions appeared in 4.4 BSD.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

SEE ALSO

strerror(3STDC)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | HISTORY | ATTRIBUTES | SEE ALSO