.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
.\"
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.\" Traducido por Miguel Pérez Ibars <mpi79470@alu.um.es> el 13-agosto-2004
.\"
.TH TIMEGM 3 "26 diciembre 2001" "GNU" "Manual del Programador de Linux"
.SH NOMBRE
timegm, timelocal \- funciones inversas para gmtime y localtime
.SH SINOPSIS
.nf
.B #include <time.h>
.sp
.BI "time_t timelocal (struct tm *" tm );
.sp
.BI "time_t timegm (struct tm *" tm );
.SH DESCRIPCIÓN
Las funciones
.B timelocal()
y
.B timegm()
son las inversas de
.BR localtime (3)
y
.BR gmtime (3).
.SH OBSERVACIONES
Estas funciones son extensiones de GNU.
La función
.B timelocal()
es equivalente a la función del estándar POSIX
.BR mktime (3).
No hay razón para usarla.
.LP
Para obtener una versión portable de
.BR timegm() ,
asigne a la variable de entorno
.B TZ
el valor UTC, llame a
.B mktime()
y restablezca el valor de
.BR TZ .
Algo así como

.RS
.nf
#include <time.h>
#include <stdlib.h>

time_t my_timegm (struct tm *tm) {
    time_t ret;
    char *tz;

    tz = getenv("TZ");
    setenv("TZ", "", 1);
    tzset();
    ret = mktime(tm);
    if (tz)
        setenv("TZ", tz, 1);
    else
        unsetenv("TZ");
    tzset();
    return ret;
}
.fi
.RE
.SH "VÉASE TAMBIÉN"
.BR gmtime (3),
.BR localtime (3),
.BR mktime (3),
.BR tzset (3)