Represents an entire time zone including all historical, current, and future time zone shift rules for daylight saving time.

Quick Info

typedef struct { 
    WORD     wFlags;  
    LPWSTR   pwszKeyName; 
    WORD     cRules; 
    TZRULE*  rgRules; 



Indicates that the key name that represents the time zone in the Windows registry is valid. Because each time zone should always be identified by a key name, this member should always have the value TZDEFINITION_FLAG_VALID_KEYNAME.


The name of the key for this time zone in the Windows registry. This name must not be localized. It has a maximum size of MAX_PATH, which is defined in the Windows Software Development Kit (SDK) header file windows.h.


The number of time zone rules for this definition. The maximum number of rules is TZ_MAX_RULES.


An array of rules that describe when shifts occur.


There must be at least one rule in rgRules. The first rule in rgRules is considered to be the rule to use until the second rule starts, regardless of the stStart on the first rule.

The rules should be sorted from oldest to newest. There is no overlap allowed between rules, so a prior rule is deemed to end when a new rule starts.

See also

Community Additions