Year 2038 Problem - Solutions

Solutions

There is no universal solution for the Year 2038 problem. Any change to the definition of the time_t data type would result in code compatibility problems in any application in which date and time representations are dependent on the nature of the signed 32-bit time_t integer. For example, changing time_t to an unsigned 32-bit integer, which would extend the range to the year 2106, would adversely affect programs that store, retrieve, or manipulate dates prior to 1970, as such dates are represented by negative numbers.

Most operating systems designed to run on 64-bit hardware already use signed 64-bit time_t integers, effectively eliminating the Year 2038 problem in any software that has been developed to use the extended format. Using a signed 64-bit value introduces a new wraparound date that is over twenty times greater than the estimated age of the universe: approximately 292 billion years from now, at 15:30:08 on Sunday, 4 December 292,277,026,596. The ability to make computations on dates is limited by the fact that tm_year uses a signed 32 bit int value starting at 1900 for the year. This limits the year to a maximum of 2,147,485,547 (2,147,483,647 + 1900). While this solves the problem for executing programs, it does not, however, solve the problem of storing date values within binary data files, many of which employ rigid storage formats.

Starting with NetBSD version 6.0 (released in October 2012), the NetBSD operating system uses a 64-bit time_t for both 32-bit and 64-bit architectures. Applications that were compiled for an older NetBSD release with 32-bit time_t are supported via a binary compatibility layer, but such older applications will still suffer from the Year 2038 problem.

Alternative proposals have been made (some of which are in use), such as storing either milliseconds or microseconds since an epoch (typically either 1 January 1970 or 1 January 2000) in a signed 64-bit integer, providing a minimum of 300,000 years range. Other proposals for new time representations provide different precisions, ranges, and sizes (almost always wider than 32 bits), as well as solving other related problems, such as the handling of leap seconds. In particular, TAI64 is an implementation of the Temps Atomique International standard, the current international real-time standard for defining a second and frame of reference.