view uptools/atcmd/settime.c @ 407:19e5a3e2f9c0

fcup-settime: moved time() retrieval a little closer to the output A fundamental problem with all simple time transfer tools is that there is always some delay between the time retrieval on the source system and that transmitted time being set on the destination, and the resulting time on the destination system is off by that delay amount. This delay cannot be fully eliminated when working in a simple environment like ours, but we should make our best effort to minimize it. In the present case, moving the atinterf_init() call before the time() retrieval should make a teensy-tiny improvement.
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 11 Aug 2018 21:52:17 +0000
parents b61b81d3cece
children dc2fd8e6f42c
line wrap: on
line source

/*
 * This utility sends an AT+CCLK command to the GSM device to set its time
 * to the host's notion of local time.
 */

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "../../rvinterf/include/exitcodes.h"

main(argc, argv)
	char **argv;
{
	int c;
	extern int optind;
	time_t unixtime;
	struct tm *tm;
	char command[32];

	while ((c = getopt(argc, argv, "B:np:RX:")) != EOF)
		if (!atinterf_cmdline_opt(c)) {
			/* error msg already printed */
			exit(ERROR_USAGE);
		}
	if (argc != optind) {
		fprintf(stderr, "usage: %s [options]\n", argv[0]);
		exit(ERROR_USAGE);
	}
	atinterf_init();
	time(&unixtime);
	tm = localtime(&unixtime);
	sprintf(command, "AT+CCLK=\"%02d/%02d/%02d,%02d:%02d:%02d%+03d\"",
		tm->tm_year % 100, tm->tm_mon + 1, tm->tm_mday,
		tm->tm_hour, tm->tm_min, tm->tm_sec, tm->tm_gmtoff / (15*60));
	atinterf_exec_cmd_needok(command, 0, 0);
	exit(0);
}