# PRTimeParameters

A representation of time zone information.

## Syntax

```{code}
#include <prtime.h>

typedef struct PRTimeParameters {
    PRInt32 tp_gmt_offset;
    PRInt32 tp_dst_offset;
} PRTimeParameters;
```

## Description

Each geographic location has a standard time zone, and if Daylight
Saving Time (DST) is practiced, a daylight time zone. The
{ref}`PRTimeParameters` structure represents the local time zone
information in terms of the offset (in seconds) from GMT. The overall
offset is broken into two components:

`tp_gmt_offset`

: The offset of the local standard time from GMT.

`tp_dst_offset`

: If daylight savings time (DST) is in effect, the DST adjustment from
  the local standard time. This is most commonly 1 hour, but may also
  be 30 minutes or some other amount. If DST is not in effect, the
  tp_dst_offset component is 0.

For example, the US Pacific Time Zone has both a standard time zone
(Pacific Standard Time, or PST) and a daylight time zone (Pacific
Daylight Time, or PDT).

- In PST, the local time is 8 hours behind GMT, so `tp_gmt_offset` is
  -28800 seconds. `tp_dst_offset` is 0, indicating that daylight
  saving time is not in effect.
- In PDT, the clock is turned forward by one hour, so the local time is
  7 hours behind GMT. This is broken down as -8 + 1 hours, so
  `tp_gmt_offset` is -28800 seconds, and `tp_dst_offset` is 3600
  seconds.

A second example is Japan, which is 9 hours ahead of GMT. Japan does not
use daylight saving time, so the only time zone is Japan Standard Time
(JST). In JST `tp_gmt_offset` is 32400 seconds, and `tp_dst_offset`
is 0.