C date and time functions
C standard library header file
The C date and time functions are a group of functions in the standard library of the C programming language implementing date and time manipulation operations. They provide support for time acquisition, conversion between date formats, and formatted output to strings.
History
The format string used in strftime traces back to at least PWB/UNIX 1.0, released in 1977. Its date system command includes various formatting options. In 1989, the ANSI C standard is released including strftime and other date and time functions.
Overview of functions
The C date and time operations are defined in the <time.h> header file (<ctime> header in C++).
The timespec and related types were originally proposed by Markus Kuhn to provide a variety of time bases, but only TIME_UTC was accepted. The functionalities were, however, added to C++ with the release of C++20 in std::chrono.
Example
The following C source code prints the current time to the standard output stream.
The public source identifies “C date and time functions” as c standard library header file. This brief keeps that definition visible, then builds a research path around date, time and functions.
Why this record matters
A short description can identify a subject without explaining its stakes. For “C date and time functions”, the useful work is to connect “c standard library header file” to the records capable of establishing context and consequence.
Place names and jurisdictional language are key evidence: both can reveal earlier catalogue descriptions and overlooked record series. The source revision retrieved here is dated Feb 8, 2026. The linked authority identifier is Q306163. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1977 and 1989.
A single description cannot reconcile every naming convention, rebuilding phase or administrative transfer associated with a place. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “C date and time functions”, its source revision and the description used here.
- Expand the search: follow C date and time functions primary sources, C date and time functions archive and date research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “C date and time functions”?
- Which authority defined the place, boundary or structure at the relevant date?
- Which earlier names or jurisdictions may reveal additional records?
Search terms from this dossier
This entry incorporates text from “C date and time functions” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.