Warning: main(/www/www/htdocs/style/globals.php) [function.main]: failed to open stream: No such file or directory in /www/www/docs/6.4.1/neutrino/lib_ref/t/tzset.html on line 1
Warning: main() [function.include]: Failed opening '/www/www/htdocs/style/globals.php' for inclusion (include_path='.:/www/www/common:/www/www/php/lib/php') in /www/www/docs/6.4.1/neutrino/lib_ref/t/tzset.html on line 1
Warning: main(/www/www/htdocs/style/header.php) [function.main]: failed to open stream: No such file or directory in /www/www/docs/6.4.1/neutrino/lib_ref/t/tzset.html on line 8
Warning: main() [function.include]: Failed opening '/www/www/htdocs/style/header.php' for inclusion (include_path='.:/www/www/common:/www/www/php/lib/php') in /www/www/docs/6.4.1/neutrino/lib_ref/t/tzset.html on line 8
Set the time according to the current time zone
#include <time.h>
void tzset( void );
libc
Use the -l c option to
qcc
to link against this library.
This library is usually included automatically.
The tzset() function sets the
global variables daylight, timezone and tzname
according to the value of the TZ environment variable, or to
the value of the _CS_TIMEZONE configuration string if
TZ isn't set.
The global variables have the following values after tzset() is executed:
- daylight
- Zero indicates that daylight saving time isn't supported in the
locale; a nonzero value indicates that daylight saving time is
supported in the locale.
This variable is cleared or set after a call to the tzset()
function, depending on whether or not a daylight saving time
abbreviation
is specified in the TZenvironment variable.
- timezone
- The number of seconds that the local time zone is earlier
than Coordinated Universal Time (UTC) (formerly known as Greenwich
Mean Time (GMT)).
- tzname
- A two-element array pointing to strings giving the abbreviations for
the name of the time zone when standard and daylight saving time are in
effect.
The time that you set on the computer with the
date command
reflects Coordinated Universal Time (UTC). The environment variable
TZ is used to establish the local time zone.
For more information, see
“Setting the time zone”
in the Configuring Your Environment chapter of the
Neutrino User's Guide.
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void print_zone()
{
char *tz;
printf( "TZ: %s\n", (tz = getenv( "TZ" ))
? tz : "default EST5EDT" );
printf( " daylight: %d\n", daylight );
printf( " timezone: %ld\n", timezone );
printf( " time zone names: %s %s\n",
tzname[0], tzname[1] );
}
int main( void )
{
tzset();
print_zone();
setenv( "TZ", "PST8PDT", 1 );
tzset();
print_zone();
return EXIT_SUCCESS;
}
produces the output:
TZ: default EST5EDT
daylight: 1
timezone: 18000
time zone names: EST EDT
TZ: PST8PDT
daylight: 1
timezone: 28800
time zone names: PST PDT
POSIX 1003.1 XSI
Safety: | |
Cancellation point |
No |
Interrupt handler |
No |
Signal handler |
No |
Thread |
Yes |
ctime(),
daylight,
localtime(),
localtime_r(),
mktime(),
strftime()
timezone,
tzname
“Setting the time zone”
in the Configuring Your Environment chapter of the
Neutrino User's Guide
Warning: main(/www/www/htdocs/style/footer.php) [function.main]: failed to open stream: No such file or directory in /www/www/docs/6.4.1/neutrino/lib_ref/t/tzset.html on line 198
Warning: main() [function.include]: Failed opening '/www/www/htdocs/style/footer.php' for inclusion (include_path='.:/www/www/common:/www/www/php/lib/php') in /www/www/docs/6.4.1/neutrino/lib_ref/t/tzset.html on line 198