Standard C Date/Time Library: Programming the World's Calendars and Clocks [Paperback]

Lance Latham (Author)

Book Description

Publication Date: May 1, 1998 | ISBN-10: 0879304960 | ISBN-13: 978-0879304966 | Edition: 1

Does the year 2000 have you sweating late-night code? Use our complete library of C programming functions to master Y2K, time on the Net, ISO 8601, time stamp compression, or any other time/date application you encounter. Using the astronomers Julian Day'

Programming functions to help you master 'Y2K', time on the net, ISO 8601, time stamp compression, or any other time/date application you encounter.

Editorial Reviews

Amazon.com Review

Lance Latham's Standard C Date/Time Library aims to solve the problem with time and calendars on computers. This book publishes the author's C library with functions (included on CD-ROM) for many of the world's calendars, interspersed with some truly fascinating historical material that makes sense of humankind's myriad attempts to get a handle on time.

The Standard C Date/Time Library begins with a description of the Y2K problem. The author then proceeds to show that definitions of years, months, and days are subject to different standards, many of which are the result of "applied astronomy." He develops his comprehensive solution using the Julian calendar and represents hours and minutes as fractions of days. His Standard C Date/Time Library (STDTL) offers extremely comprehensive functionality, allowing you to calculate differences between days and days of the week, as well as calculations for holidays.

The author intersperses source code listings with wide-ranging descriptions of calendars and their inconsistencies. For the treatment of the Western calendar and ISO 8601 standard time functions, this code library is worth it. However, the author goes much further and offers code for and descriptions of all the major calendars of the world, including non-Western calendars and ancient calendar systems. --Richard Dragan

About the Author

Lance Latham is the principal of Resource Management Systems, Inc., a software development firm in McAllen, Texas, and has been programming on a wide range of platforms for three decades. Although he has programmed in more languages than he wants to count, Lance now primarily codes in C for developing systems that manage critical resources in enterprises ranging from health care to jewelry marketing.

Product Details

• Paperback: 560 pages
• Publisher: CMP; 1 edition (May 1, 1998)
• Language: English
• ISBN-10: 0879304960
• ISBN-13: 978-0879304966
• Product Dimensions: 8.8 x 7.1 x 1.5 inches
• Shipping Weight: 2.4 pounds
• Average Customer Review: 4.0 out of 5 stars  See all reviews (7 customer reviews)
• Amazon Best Sellers Rank: #1,323,159 in Books (See Top 100 in Books)
  • #83 in Books > Computers & Technology > Programming > C > Language

Customer Reviews

Most Helpful Customer Reviews

8 of 9 people found the following review helpful:

2.0 out of 5 stars Beware: bugs ahead!, November 14, 2001

By 

P. Curtis (UK) - See all my reviews
(REAL NAME)   

This review is from: Standard C Date/Time Library: Programming the World's Calendars and Clocks (Paperback)

I purchased this book out of interest, but then, as always, there comes a time when you reach for a reference book to help out when you need something coded. Well, that's what I did, and unfortunately the book has basic errors in its Julian to Gregorian conversion routine. Minor, I know, but this book is billed as "the Y2K buster" to get on the bandwagon, but the supplied (tested! hah!) routines don't actually work.

I went to the support web site to look up or report this errata. It's gone. Unforgivable. The correct algorithm is available from (the U.S. Naval Observatory's website). The transcription error from this algorithm in Fortran to C is minor, but enough to get me irate. A book that is sold on accuracy and Y2K busting should get dates right. You'd have thought that given a function and it's inverse, that the author would have checked that f(f^-1(x)) == x and f^-1(f(x)) == x. But no...

Apart from that, you'll never use many of the other calendric functions. My faith in this tome is severly shaken.

5 of 5 people found the following review helpful:

5.0 out of 5 stars A superb handbook for date/time programming, December 4, 1998

By 

Clinton Anderson ([e-mail]) (DeKalb, Illinois) - See all my reviews

This review is from: Standard C Date/Time Library: Programming the World's Calendars and Clocks (Paperback)

If you are a computer programmer, don't write any (more) date/time code until you see how Lance Latham does it! This book contains comprehensive, organized solutions to all the date/time problems you are likely to encounter, including tricky ones such as "What is the date N days after date X?," "How many days, exactly, are there between date X and date Y?," and even "What is my client's holiday schedule next year?"

Even if you think you already have an adequate library of date/time code in your shop, don't be too sure until you've tested it using the methods illustrated in Lance Latham's own test programs, included in the CD that accompanies the book. The Year 2000 bug is not the only one infesting date/time code!

For programmers with historical, international, or religious calendar problems to solve, this book is an invaluable reference for a wide range of past and present calendars and timekeeping systems. Lance Latham also includes a section on the forward-looking ISO 8601 standard, which is enjoying increasing usage in Europe.

I recommend this book even if you write computer programs in some language other than C. The routines in this book are easy to translate into other languages, even for programmers with only a "reading" knowledge of C. The correct usage of the routines is exhaustively documented, with all parameters, returns, and limitations spelled out for you. Whichever language you use, following Lance Latham's approach will lead to concise, fast, and reliable code.

My only caveat about this book is that the algorithms underlying the routines are not always adequately explained. Sometimes we are told no more than that an algorithm is a "standard Gregorian proleptic calendar conversion routine." Testing will verify that it does somehow give the correct results, but you may still be tempted to spend hours studying it to figure out how it works.

4 of 4 people found the following review helpful:

5.0 out of 5 stars More than just algorithms, January 19, 1999

By A Customer

This review is from: Standard C Date/Time Library: Programming the World's Calendars and Clocks (Paperback)

This isn't merely a list of algorithms (though the number of included date/time programs is extensive); it gives a background and an explanation for the major calendar systems and many of the obscure ones. So I'd recommend it not just for "C programmers" but to anyone who cares about calendars and their vagaries.