#include "header.h"

void err_normal(const char *fmt, ...) {
	va_list args;
	
	va_start(args, fmt);        /* initialize */
	__process_error(fmt, args); /* process this error */
	va_end(args);
}

void err_fatal(const char *fmt, ...) {
	va_list args;
	
	va_start(args, fmt);        /* initialize */
	__process_error(fmt, args); /* process this error */
	va_end(args);
	exit(1);                    /* exit gracefully */
}

void __process_error(const char *fmt, va_list args) {
	int error;
	
	/*
	 * Save errno, to make sure we can restore it if one of the following
	 * function calls changes it for some reason.
	 */
	error = errno;
	
	/*
	 * Print: 1. caller's error message,
	 *        2. system error message if applicable,
	 *        3. add newline charater.
	 */
	vfprintf(stderr, fmt, args);
	if (error != 0) { /* a system error has occurred */
		fprintf(stderr, ": %s", strerror(error));
		putc('\n', stderr);
	}
}