## 1904-12-01 00:00:00 ~ 00:29:59
## 1932-01-01 00:00:00 ~ 00:29:59
## 1961-08-10 00:00:00 ~ 00:29:59
## 1968-10-01 00:00:00 ~ 00:29:59

## mktime() 분 단위 덧셈 오류(뒤로 30분 늦어지거나 overflow)
## date() 정확한 unix timestamp 에 대해서 30분 빨리짐

// date() 정확한 unix timestamp 에 대해서 30분 빨리짐
//
echo ($t = mktime(23,59,0,11,30,1904))."\n"; // -2053931460 (1904-11-30
23:59:00)
echo ($t + 60*1)."\n";			// -2053931400 (1904-12-01 00:30:00) F
echo ($t + 60*2)."\n";			// -2053931340 (1904-12-01 00:31:00) F
echo ($t + 60*30)."\n";			// -2053929660 (1904-12-01 00:59:00) F
echo ($t + 60*31)."\n";			// -2053929600 (1904-12-01 01:00:00) F
echo "\n";

// mktime() 분 단위 오류
//
echo mktime(23,59,0,11,30,1904)."\n";	// -2053931460 (1904-11-30
23:59:00)
echo mktime(0,0,0,12,1,1904)."\n";	// -2053933200 (1904-11-30 23:30:00) F
echo mktime(0,1,0,12,1,1904)."\n";	// -2053933140 (1904-11-30 23:31:00) F
echo mktime(0,29,0,12,1,1904)."\n";	// -2053931460 (1904-11-30 23:59:00)
F
echo mktime(0,30,0,12,1,1904)."\n";	// -2053931400 (1904-12-01 00:30:00)
echo "\n";

// mktime() 분 단위 overflow
//
echo mktime(23,59,0,11,30,1904)."\n";	// -2053931460 (1904-11-30
23:59:00)
echo mktime(23,60,0,11,30,1904)."\n";	// -2 (1970-01-01 08:59:58) F
echo mktime(23,61,0,11,30,1904)."\n";	// -2 (1970-01-01 08:59:58) F
echo mktime(23,89,0,11,30,1904)."\n";	// -2 (1970-01-01 08:59:58) F
echo mktime(23,90,0,11,30,1904)."\n";	// -2053931400 (1904-12-01
00:30:00)
echo "\n";

// date() 정확한 unix timestamp 에 대해서 30분 빨리짐
//
echo mktime(23,59,0,11,30,1904)."\n";	// -2053931460 (1904-11-30
23:59:00)
echo mktime(23,59,60,11,30,1904)."\n";	// -2053931400 (1904-12-01
00:30:00) F
echo mktime(23,59,120,11,30,1904)."\n";	// -2053931340 (1904-12-01
00:31:00) F
echo mktime(23,59,1800,11,30,1904)."\n";// -2053929660 (1904-12-01
00:59:00) F
echo mktime(23,59,1860,11,30,1904)."\n";// -2053929600 (1904-12-01
01:00:00) F
echo "\n";