C date and time functions


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.

Overview of functions

The C date and time operations are defined in the time.h header file.
IdentifierDescription
Time
manipulation		computes the difference in seconds between two time_t values
Time
manipulation		returns the current time of the system as a time_t value, number of seconds,. The value of the epoch is operating system dependent; 1900 and 1970 are often used. See RFC 868.
Time
manipulation		returns a processor tick count associated with the process
Format
conversions		converts a struct tm object to a textual representation
Format
conversions		converts a time_t value to a textual representation
Format
conversions		converts a struct tm object to custom textual representation
Format
conversions		converts a struct tm object to custom wide string textual representation
Format
conversions		converts a time_t value to calendar time expressed as Coordinated Universal Time
Format
conversions		converts a time_t value to calendar time expressed as local time
Format
conversions		converts calendar time to a time_t value.
Constantsnumber of processor clock ticks per second
Typesbroken-down calendar time type: year, month, day, hour, minute, second
Typesarithmetic time type
Typesprocess running time type

Example

The following C source code prints the current time to the standard output stream.

  1. include
  2. include
  3. include
int main

The output is:

Current time is Thu Sep 15 21:18:23 2016