CGoodTime -- A Y2.038K-Safe Replacement for CTime

The MFC CTime class uses the time_t "structure" internally to store its data. This means that it stores time/date as a signed 32-bit count of milliseconds since January 1, 1970. While this makes it safe for the dreaded year 2000, this counter will wrap sometime in early 2038. As a result, CTime stops functioning for any date from January 2038 and up.

Now I expect that all of my users will have upgraded to version 42 of my program by that point, but thinking like that is where the Y2K bugs came from in the first place. Besides, when customers or management press for information on Y2K compliance, it can be embarrassing to have to explain why the year 2038 is in the critical path. It's just easier to fix it.

So without further ado, I introduce my solution. I have re-written the CTime class using the tm structure in place of the time_t structure for internal storage. My new class is CGoodTime.

I have attempted to keep the interface consistent with the original CTime class with the intention that this would be a straight drop-in replacement. I believe I have succeeded in this goal with three exceptions.

  1. Methods that have time_t as parameters or return values in CTime have tm values in their place, since interfacing with time_t's would defeat the purpose.
  2. I dropped support for the operators which return CTimeSpan. I didn't need these, so I leave it as an exercise to you to implement these if you need them.
  3. I dropped support for the '#' character in the Format strings. See 2.

The sample project I've included here uses the CGoodTime class and the CTime class to produce text output of all ways a time can be represented with the the Format function. A radio button controls whether the output is in local time or Greenwich Mean Time. For dates prior to 2038, the two strings should match exactly. For dates 2038 and later, CTime does not produce output.

Download demo project - 19 KB

Download source - 6 KB



Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Lenovo recommends Windows 8 Pro. "I dropped my laptop getting out of the taxi." This probably sounds familiar to most IT professionals. If your employees are traveling, you know their devices are in for a rough go. Whether it's a trip to the conference room or a convention out of town, any time equipment leaves a user's desk it is at risk of being put into harm's way. Stay connected at all times, whether at the office or on the go, with agile, durable, and flexible devices like the Lenovo® …

  • U.S. companies are desperately trying to recruit and hire skilled software engineers and developers, but there's simply not enough quality talent to go around. In response, companies often resort to inferior solutions -- hiring substandard developers and engineers, recruiting talent on a part-time or temporary basis, poaching people from competitors, or burdening an already stressed IT staff for more of their labor. Fortunately, there's a better solution. Read this white paper to learn the business value of …

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date