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