/* error.c -- report an error, then die
 * 
 * char	*format;
 * error(format, arg1, arg2, ...)
 *
 * error is called like printf.  It writes the specified error message
 * on stderr, preceded by the program name (obtained from the global
 * char *PROGNAME) and followed by a newline, then exits with status
 * ERROR.  
 *
 * error1 is identical to error.  It is present for the convenience of
 * earlier programs that were written without the varargs possibility,
 * and had to call a different routine to pass an argument.
 *
 * verror is the varargs version of error.  It is called using:
 *
 #include <stdargs.h>
 *
 * char		*format;
 * va_list	ap;
 * verror(format, ap);
 */
#include <stdio.h>
#include <stdarg.h>
#include "common.h"

void	error(const char *, ...);
void	error1(const char *, ...);
void	verror(const char *, va_list);

extern	char	*PROGNAME;

void
error(
    const char *f,
    ...
) {
    va_list		ap;

    va_start(ap, f);
    verror(f, ap);
    va_end(ap);
}

void
error1(
    const char *f,
    ...
) {
    va_list		ap;

    va_start(ap, f);
    verror(f, ap);
    va_end(ap);
}

void
verror(
    const char *f,
    va_list ap
) {
    fprintf(stderr, "%s: ", PROGNAME);
    vfprintf(stderr, f, ap);
    putc('\n', stderr);
    perror(PROGNAME);
    exit(ERROR);
}