# CFCalendarComposeAbsoluteTime Computes the absolute time from components in a description string. ``` extern Boolean CFCalendarComposeAbsoluteTime(CFCalendarRef calendar, CFAbsoluteTime *at, const char *componentDesc, ...); ``` ## Parameters `calendar` The calendar to use for the computation. `at` Upon return, contains the computed absolute time. `componentDesc` A string that describes the components provided in the varidaic parameters giving the amounts of each calendrical component in the order specified by `componentDesc`. The amounts to add may be negative, zero, positive, or any combination thereof. ## Return Value `TRUE`—and in `at` the absolute time computed from the given components—if the `componentDesc` description string can be converted into an absolute time, otherwise `FALSE`. Also returns `FALSE` for out-of-range values. ## Discussion When there are insufficient components provided to completely specify an absolute time, a calendar uses default values of its choice. When there is inconsistent information, a calendar may ignore some of the parameters or the function may return `FALSE`. Unnecessary components are ignored (for example, Day takes precedence over Weekday + Weekday ordinal). Note that some computations can take a relatively long time to perform. The following example shows how to use this function to initialize an absolute time, `at`, to 6 January 1965 14:10:00, for a given calendar `gregorian` . ```objc CFCalendarComposeAbsoluteTime(gregorian, &at, "yMdHms", 1965, 1, 6, 14, 10, 00); ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)