asctime

char* asctime (const struct tm * timeptr);

Convert tm structure to string

Interprets the contents of the tm structure pointed by timeptr as a calendar time and converts it to a C-string containing a human-readable version of the corresponding date and time.

The returned string has the following format:

Www Mmm dd hh:mm:ss yyyy

Where Www is the weekday, Mmm the month (in letters), dd the day of the month, hh:mm:ss the time, and yyyy the year.

The string is followed by a new-line character ('\n') and terminated with a null-character.

It is defined with a behavior equivalent to:

char* asctime(const struct tm *timeptr)
{
 static const char wday_name[][4] = {
 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 };
 static const char mon_name[][4] = {
 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 };
 static char result[26];
 sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
 wday_name[timeptr->tm_wday],
 mon_name[timeptr->tm_mon],
 timeptr->tm_mday, timeptr->tm_hour,
 timeptr->tm_min, timeptr->tm_sec,
 1900 + timeptr->tm_year);
 return result;
}

For an alternative with custom date formatting, see strftime .

Parameters

timeptr: Pointer to a tm structure that contains a calendar time broken down into its components (see struct tm ).

Return Value

A C-string containing the date and time information in a human-readable format.

The returned value points to an internal array whose validity or value may be altered by any subsequent call to asctime or ctime .

Example

/* asctime example */
#include <stdio.h> /* printf */
#include <time.h> /* time_t, struct tm, time, localtime, asctime */
int main ()
{
 time_t rawtime;
 struct tm * timeinfo;
 time ( &rawtime );
 timeinfo = localtime ( &rawtime );
 printf ( "The current date/time is: %s", asctime (timeinfo) );
 return 0;
}

Output:


The current date/time is: Wed Feb 13 15:46:11 2013

Data races

The function accesses the object pointed by timeptr.
The function also accesses and modifies a shared internal buffer, which may cause data races on concurrent calls to asctime or ctime . Some libraries provide an alternative function that avoids this data race: asctime_r (non-portable).

Exceptions (C++)

No-throw guarantee: this function never throws exceptions.

functions

macros

types