std::ctime

 

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C-style date and time

 

C-style date and time utilities

Functions

Time manipulation

difftime

time

clock

timespec_get (C++17)

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asctime

ctime

strftime

wcsftime

gmtime

localtime

mktime

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tm

time_t

clock_t

timespec (C++17)

 

Defined in header <ctime>
char* ctime( const std::time_t* time );

Converts given time since epoch to a calendar local time and then to a textual representation, as if by calling std::asctime(std::localtime(time)). The resulting string has the following format:

Www Mmm dd hh:mm:ss yyyy\n

• Www - the day of the week (one of Mon, Tue, Wed, Thu, Fri, Sat, Sun).
• Mmm - the month (one of Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec).
• dd - the day of the month
• hh - hours
• mm - minutes
• ss - seconds
• yyyy - years

The function does not support localization.

Parameters

time

-

pointer to a std::time_t object specifying the time to print

Return value

Pointer to a static null-terminated character string holding the textual representation of date and time. The string may be shared between std::asctime and std::ctime, and may be overwritten on each invocation of any of those functions.

Notes

This function returns a pointer to static data and is not thread-safe. In addition, it modifies the static std::tm object which may be shared with std::gmtime and std::localtime. POSIX marks this function obsolete and recommends std::strftime instead.

The behavior may be undefined for the values of std::time_t that result in the string longer than 25 characters (e.g. year 10000)

Example

Run this code

#include <ctime>
#include <cstring>
#include <cassert>
#include <iostream>
 
int main()
{
    std::time_t result = std::time(nullptr);
    std::cout << std::ctime(&result);
 
    char buffer[32];
    std::strncpy(buffer, std::ctime(&result), 26);
    assert('\n' == buffer[std::strlen(buffer)-1]);
    std::cout << buffer;
}

Possible output:

Mon Oct 11 17:10:55 2021
Mon Oct 11 17:10:55 2021

See also

asctime	converts a std::tm object to a textual representation (function)
strftime	converts a std::tm object to custom textual representation (function)
put_time (C++11)	formats and outputs a date/time value according to the specified format (function template)