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    PRTimeParameters

    A representation of time zone information.

    Syntax

     #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 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.

    Document Tags and Contributors

    Contributors to this page: Sheppy, teoli
    Last updated by: teoli,
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