Ihave come across an error in Dataflex 19.0 and 19.1 and presumably inall previous versions too. Dataflex treats centenary years that arenot divisible by 400 as leap years. According to the Gregoriancalendar these are not leap years. So 1600 and 2000 are leap yearsbut 1700, 1800, and 1900 are not. Entering 29/02/1900 as a date inDataflex does not produce and error and the date is translated to anumeric value between that generated by 28/02/1900 and 01/03/1900.Here is an example of what numeric values are calculated in 1700:

Date Dataflex numeric value - but should be
01/03/1700 620985 620987
29/02/1700 620984 invalid
28/02/1700 620983 620986

Thisonly came to light when I was rewriting my family history software inWindows Dataflex and was reading pre-existing embedded Dataflexdatafiles which I had created nearly twenty years ago usingnon-Dataflex software. The results in Dataflex show dates prior to1900 as out of kilter by virtue of the interpretation of the numericvalue.