VariantTimeToDosDateTime function (oleauto.h)

Article
10/13/2021

Converts the variant representation of a date and time to MS-DOS date and time values.

Syntax

INT VariantTimeToDosDateTime(
  [in]  DOUBLE vtime,
  [out] USHORT *pwDosDate,
  [out] USHORT *pwDosTime
);

Parameters

[in] vtime

The variant time to convert.

[out] pwDosDate

Receives the converted MS-DOS date.

[out] pwDosTime

Receives the converted MS-DOS time

Return value

The function returns TRUE on success and FALSE otherwise.

Remarks

A variant time is stored as an 8-byte real value (double), representing a date between January 1, 100 and December 31, 9999, inclusive. The value 2.0 represents January 1, 1900; 3.0 represents January 2, 1900, and so on. Adding 1 to the value increments the date by a day. The fractional part of the value represents the time of day. Therefore, 2.5 represents noon on January 1, 1900; 3.25 represents 6:00 A.M. on January 2, 1900, and so on. Negative numbers represent the dates prior to December 30, 1899.

For a description of the MS-DOS date and time formats, see DosDateTimeToVariantTime.

The VariantTimeToDosDateTime function will accept invalid dates and try to fix them when resolving to a VARIANT time. For example, an invalid date such as 2/29/2001 will resolve to 3/1/2001. Only days are fixed, so invalid month values result in an error being returned. Days are checked to be between 1 and 31. Negative days and days greater than 31 results in an error. A day less than 31 but greater than the maximum day in that month has the day promoted to the appropriate day of the next month. A day equal to zero resolves as the last day of the previous month. For example, an invalid dates such as 2/0/2001 will resolve to 1/31/2001.

Requirements

Requirement	Value
Target Platform	Windows
Header	oleauto.h
Library	OleAut32.lib
DLL	OleAut32.dll

Share via