Weird bug

Let’s say, for example, that a system supplies you the time of some event in UTC, you convert it to local and shove the date/time up on the display. Say, for argument’s sake, you also include the Day Of Week, ending up with a format of DD/MM, DOW HH:MM. Everything looks fine, until someone notices that the Day Of Week is wrong. The 28th of May is a Wednesday, not a Thursday.

What happened?

The date conversion routine that generates the DOW string does a bunch of odd stuff, but seems to work correctly; it certainly works in other parts of the code, and generates the right string there.


The UTC time seemed to be converted to local time twice, but that wasn’t the culprit; surprisingly, no-one is killed in an explosion of silicon splinters when that code is double-executed. Whatever.

Could it be that the system supplying you the time of that event in UTC is off by a year? One year into the future. That would give you that behaviour.

Check it.

2 thoughts on “Weird bug

  1. josh Post author

    Or it could also be saying that the year is 2116 – the lesson? Don’t trust anyone, not even host systems.

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