wctime

Name

wasctime, wctime
-transforms date and time to a wide char string to the form: Sun Sep 16 01:03:52 1973

Library

libc.lib

Synopsis

#include <wchar.h>

wchar_t * wctime (const time_t *clock);

wchar_t * wasctime (const struct tm *tm);

Return values

The functions wasctime and wctime return a pointer to the resulting wide-character string.

Detailed description

The function wctime, takes a time value representing, the time in seconds since the Epoch (00:00:00 UTC, January 1, 1970); as an argument. See time

The function wctime adjusts the time value for the current time zone in the same manner as localtime, and returns a pointer to a 26-wide character string of the form:

Thu Nov 24 18:22:48 1986\n\0

All the fields have constant width.

The function wasctime converts the broken down time in the structure tm pointed at, by *tm to the form shown in the example above.

External declarations as well as the tm structure definition are in the

#include <time.h>include file. The tm structure includes at least the following fields:

int tm_sec;     /* seconds (0 - 60) */
int tm_min;     /* minutes (0 - 59) */
int tm_hour;    /* hours (0 - 23) */
int tm_mday;    /* day of month (1 - 31) */
int tm_mon;     /* month of year (0 - 11) */
int tm_year;    /* year - 1900 */
int tm_wday;    /* day of week (Sunday = 0) */
int tm_yday;    /* day of year (0 - 365) */
int tm_isdst;   /* is summer time in effect? */
char *tm_zone;  /* abbreviation of timezone name */
long tm_gmtoff; /* offset from UTC in seconds */

The field tm_isdst is non-zero if summer time is in effect.

The field tm_gmtoff is the offset (in seconds) of the time represented from UTC, with positive values indicating east of the Prime Meridian.

Examples

//Example usage of wasctime and wctime:
#include <time.h>
#include <stdio.h>
int main(){
        time_t t;
        struct tm *timeptr;
        wchar_t* wasc_time;
        t = time (NULL); //Get current time in seconds from Epoc
        //Fill tm struct w.r.t localtime using localtime
        timeptr = localtime (&t);
        //Use this to convert it to a string indicating time w.r.t localtime
        wasc_time = wasctime (timeptr);
        wprintf (L"Time from wasctime w.r.t localtime : %s", wasc_time);
                wprintf(L"Time from wctime w.r.t localtime : %s0, wctime(&t) );
         return 0;
}

Output

Time from wasctime w.r.t localtime : Thu Jun 22 10:42:27 2007
Time from wctime w.r.t localtime : Thu Jun 22 10:42:27 2007

Bugs

These functions leave their result in an internal static object and return a pointer to that object. Subsequent calls to these functions will modify the same object.

The C Standard provides no mechanism for a program to modify its current local timezone setting, and the POSIX -standard method is not reentrant. (However, thread-safe implementations are provided in the POSIX threaded environment.)

The tm_zone field of a returned tm structure points to a static array of characters, which will also be overwritten by any subsequent calls (as well as by subsequent call to tzset )

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