Time Functions Calculate for Daylight Savings Time (39908)


The information in this article applies to:

  • The C Run-Time (CRT), when used with:
    • Microsoft C for MS-DOS 5.1
    • Microsoft C for MS-DOS 6.0
    • Microsoft C for MS-DOS 6.0a
    • Microsoft C for MS-DOS 6.0ax
    • Microsoft C for OS/2 5.1
    • Microsoft C for OS/2 6.0
    • Microsoft C for OS/2 6.0a
    • Microsoft C/C++ for MS-DOS 7.0
    • Microsoft Visual C++ 1.0
    • Microsoft Visual C++ 1.5
This article was previously published under Q39908
The Microsoft time functions calculate for daylight saving time. In particular, mktime() will set the hour ahead or back one hour according to the rules of daylight saving time. The only way to change the dates that the time functions use in calculating daylight saving time is to get the run-time library source code available for the time functions and modify the routine _isindst() in the file TZSET.C.
Modification Type:MajorLast Reviewed:12/12/2003
Keywords:kb16bitonly KB39908
©2003 Microsoft Corporation. All rights reserved.