time, _time32, _time64

Obtiene la hora del sistema.

Sintaxis

time_t time( time_t *destTime );
__time32_t _time32( __time32_t *destTime );
__time64_t _time64( __time64_t *destTime );

Parámetros

destTime
Puntero a la ubicación de almacenamiento de tiempo.

Valor devuelto

Devuelve el tiempo transcurrido desde medianoche, 1 de enero de 1970 o -1 si se produce un error.

Comentarios

La función time devuelve el número de segundos transcurridos desde la medianoche (00:00:00) del 1 de enero de 1970, hora universal coordinada (UTC), según el reloj del sistema. El valor devuelto se almacena en la ubicación que proporciona destTime. Este parámetro puede ser NULL, en cuyo caso no se almacena el valor devuelto.

De manera predeterminada,time es un contenedor para _time64 y time_t equivalente a __time64_t. Si necesita forzar el compilador para interpretar time_t como el antiguo time_tde 32 bits, puede definir _USE_32BIT_TIME_T. No se recomienda _USE_32BIT_TIME_T, ya que la aplicación puede producir un error después del 18 de enero de 2038; el uso de esta macro no se permite en plataformas de 64 bits.

Requisitos

Routine	Encabezado C necesario	Encabezado C++ necesario
time, _time32, _time64	<time.h>	<ctime> o <time.h>

Para obtener más información sobre compatibilidad, consulte Compatibilidad.

Ejemplo

// crt_times.c
// compile with: /W3
// This program demonstrates these time and date functions:
//      time         _ftime    ctime_s     asctime_s
//      _localtime64_s    _gmtime64_s    mktime    _tzset
//      _strtime_s     _strdate_s  strftime
//
// Also the global variable:
//      _tzname
//
// Turn off deprecated unsafe CRT function warnings
#define _CRT_SECURE_NO_WARNINGS 1

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/timeb.h>
#include <string.h>

int main()
{
    char tmpbuf[128], timebuf[26], ampm[] = "AM";
    time_t ltime;
    struct _timeb tstruct;
    struct tm today, gmt, xmas = { 0, 0, 12, 25, 11, 93 };
    errno_t err;

    // Set time zone from TZ environment variable. If TZ is not set,
    // the operating system is queried to obtain the default value
    // for the variable.
    //
    _tzset();

    // Display operating system-style date and time.
    _strtime_s( tmpbuf, 128 );
    printf( "OS time:\t\t\t\t%s\n", tmpbuf );
    _strdate_s( tmpbuf, 128 );
    printf( "OS date:\t\t\t\t%s\n", tmpbuf );

    // Get UNIX-style time and display as number and string.
    time( &ltime );
    printf( "Time in seconds since UTC 1/1/70:\t%lld\n", (long long)ltime );
    err = ctime_s(timebuf, 26, &ltime);
    if (err)
    {
        printf("ctime_s failed due to an invalid argument.");
        exit(1);
    }
    printf( "UNIX time and date:\t\t\t%s", timebuf );

    // Display UTC.
    err = _gmtime64_s( &gmt, &ltime );
    if (err)
    {
        printf("_gmtime64_s failed due to an invalid argument.");
    }
    err = asctime_s(timebuf, 26, &gmt);
    if (err)
    {
        printf("asctime_s failed due to an invalid argument.");
        exit(1);
    }
    printf( "Coordinated universal time:\t\t%s", timebuf );

    // Convert to time structure and adjust for PM if necessary.
    err = _localtime64_s( &today, &ltime );
    if (err)
    {
        printf("_localtime64_s failed due to an invalid argument.");
        exit(1);
    }
    if ( today.tm_hour >= 12 )
    {
        strcpy_s( ampm, sizeof(ampm), "PM" );
        today.tm_hour -= 12;
    }
    if ( today.tm_hour == 0 )  // Adjust if midnight hour.
        today.tm_hour = 12;

    // Convert today into an ASCII string
    err = asctime_s(timebuf, 26, &today);
    if (err)
    {
        printf("asctime_s failed due to an invalid argument.");
        exit(1);
    }

    // Note how pointer addition is used to skip the first 11
    // characters and printf is used to trim off terminating
    // characters.
    //
    printf( "12-hour time:\t\t\t\t%.8s %s\n",
        timebuf + 11, ampm );

    // Print additional time information.
    _ftime( &tstruct ); // C4996
    // Note: _ftime is deprecated; consider using _ftime_s instead
    printf( "Plus milliseconds:\t\t\t%u\n", tstruct.millitm );
    printf( "Zone difference in hours from UTC:\t%u\n",
             tstruct.timezone/60 );
    printf( "Time zone name:\t\t\t\t%s\n", _tzname[0] ); //C4996
    // Note: _tzname is deprecated; consider using _get_tzname
    printf( "Daylight savings:\t\t\t%s\n",
             tstruct.dstflag ? "YES" : "NO" );

    // Make time for noon on Christmas, 1993.
    if( mktime( &xmas ) != (time_t)-1 )
    {
        err = asctime_s(timebuf, 26, &xmas);
        if (err)
        {
            printf("asctime_s failed due to an invalid argument.");
            exit(1);
        }
        printf( "Christmas\t\t\t\t%s\n", timebuf );
    }

    // Use time structure to build a customized time string.
    err = _localtime64_s( &today, &ltime );
    if (err)
    {
        printf(" _localtime64_s failed due to invalid arguments.");
        exit(1);
    }

    // Use strftime to build a customized time string.
    strftime( tmpbuf, 128,
              "Today is %A, day %d of %B in the year %Y.\n", &today );
    printf( tmpbuf );
}

OS time:            13:51:23
OS date:            04/25/03
Time in seconds since UTC 1/1/70:   1051303883
UNIX time and date:         Fri Apr 25 13:51:23 2003
Coordinated universal time:      Fri Apr 25 20:51:23 2003
12-hour time:            01:51:23 PM
Plus milliseconds:         552
Zone difference in hours from UTC:   8
Time zone name:            Pacific Standard Time
Daylight savings:         YES
Christmas            Sat Dec 25 12:00:00 1993

Today is Friday, day 25 of April in the year 2003.

Consulte también

Administración de tiempo
asctime, _wasctime
asctime_s, _wasctime_s
_ftime, _ftime32, _ftime64
gmtime, _gmtime32, _gmtime64
gmtime_s, _gmtime32_s, _gmtime64_s
localtime, _localtime32, _localtime64
localtime_s, _localtime32_s, _localtime64_s
_utime, _utime32, _utime64, _wutime, _wutime32, _wutime64