errx() -- write formatted error message

SYNOPSIS

#include <err.h>

void errx(int eval, const char *fmt, ...);

The function errx() writes a formatted error message to the standard error stream, and then exits with the specified exit value. The first part of the output line sent to standard error consists of the file name of the executable, followed by a colon and a space. If the value of fmt is not null, this is followed by a message containing the optional variables, formatted according to fmt, followed by a trailing colon and space. The output line is terminated by a linefeed.

The function errx() is roughly equivalent to

fprintf(stderr,"%s: ", argv[0]);
fprintf(stderr,fmt, ...);
fprintf(stderr,"\n");
exit(eval);

PARAMETERS

eval: Is the exit value for process.
fmt: Is the format string for optional arguments, or the null pointer if no formatted message is to be printed.
...: Represents optional arguments to the formatted message.