qcal

qcal is a term used in computing to denote a calendar calculation tool or library. There is no single standard definition, and the name has been adopted by multiple independent projects for different purposes. In general, qcal projects focus on date handling and calendar computations rather than application logic.

In many implementations, qcal tools provide core functionality for working with dates rather than full applications. Common features across implementations may include validation of Gregorian dates, leap year handling, conversion between calendar dates and serial day counts such as Julian Day Numbers, day-of-week calculation, and support for ISO week numbers. Some tools also provide calendar rendering, producing text calendars for specific months or years, or for ranges of dates.

Usage contexts vary: lightweight command-line utilities for scripting can generate calendars or perform simple date arithmetic; library variants intended for inclusion in other software provide APIs for date manipulation, arithmetic (adding or subtracting days), and formatting. In embedded or performance-constrained environments, qcal implementations may emphasize small footprint and portability.

Because the name is not associated with a single project, users encountering "qcal" should consult context-specific documentation to determine exact capabilities, syntax, and dependencies.

See also: cal, ncal, date, Julian day, ISO week date.