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The SupportsDST property retrieves a value that indicates whether a Time Zone supports Daylight-Saving Time.

HRESULT get_SupportsDST(
   VARIANT_BOOL * pfSupportsDST


[out] Reference to the Boolean flag. VARIANT_TRUE when the Time Zone supports Daylight-Saving Time. For information about the VARIANT_BOOL type, see the union member of the PROPVARIANT structure.

This method returns the standard values E_INVALIDARG, E_OUTOFMEMORY, E_UNEXPECTED, and E_FAIL, as well as the following:


The method completed successfully.

All other ITimeZone properties are defined only if the SupportsDST property is VARIANT_TRUE.

The VARIANT_BOOL data type (also known as VT_BOOL) uses the value -1 to represent TRUE and 0 to represent FALSE. It is defined in the wtypes.h header file in the following manner:

typedef short VARIANT_BOOL;

A common programming error occurs when, for readability purposes, you want to set a VARIANT_BOOL value to TRUE or FALSE. You can achieve the same effect by using the aliases VARIANT_TRUE and VARIANT_FALSE, which are also defined in the wtypes.h header file.

#define VARIANT_TRUE  ((VARIANT_BOOL)0xffff)

Windows Embedded CEWindows CE 2.0 and later
Windows MobileWindows Mobile Version 5.0 and later

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