How To Set the System Time

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Article ID: 154009 - View products that this article applies to.
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SUMMARY

The Win32 SetSystemTime API function offers the functionality to change the system time on the local machine. The change will take place immediately without the need for a reboot. This article illustrates how to create a sample project that sets the system time using the SetSystemTime function. The SetSystemTime function sets the system time based on coordinated universal time (UTC). UTC-based time is loosely defined as the current date and time of day in Greenwich, England.

MORE INFORMATION

  1. Start a new project in Visual Basic. Form1 is created by default.
  2. Add the following code to the General Declarations section of Form1:
          Option Explicit
    
          Private Type SYSTEMTIME
            wYear As Integer
            wMonth As Integer
            wDayOfWeek As Integer
            wDay As Integer
            wHour As Integer
            wMinute As Integer
            wSecond As Integer
            wMilliseconds As Integer
          End Type
    
          Private Declare Function SetSystemTime Lib "kernel32" (lpSystemTime _
            As SYSTEMTIME) As Long
    
          Private Sub Form_Load()
            Dim lReturn As Long
            Dim lpSystemTime As SYSTEMTIME
            lpSystemTime.wYear = 1996
            lpSystemTime.wMonth = 6
            lpSystemTime.wDayOfWeek = 5
            lpSystemTime.wDay = 28
            lpSystemTime.wHour = 9
            lpSystemTime.wMinute = 42
            lpSystemTime.wSecond = 0
            lpSystemTime.wMilliseconds = 0
            lReturn = SetSystemTime(lpSystemTime)
          End Sub
    
    					
  3. Run the project by pressing the F5 key. Check the system time and date in the Control Panel. The time should have changed to reflect the UTC-based time settings used in the sample.

REFERENCES

The SYSTEMTIME Type structure is as follows:
   WYear           Integer-The current year.
   WMonth          Integer-The current month. January is 1.
   WDayOfWeek      Integer-The current day of the week. Sunday is 0.
   WDay            Integer-The current day of the month.
   WHour           Integer-The current hour.
   wMinute         Integer-The current minute.
   wSecond         Integer-The current second.
   wMilliseconds   Integer-The current millisecond.
				

To change the system time on a Win32 platform from 16-bit Visual Basic, you would have to create a DLL that does a generic thunk to the 32-bit API SetSystemTime.

Properties

Article ID: 154009 - Last Review: July 13, 2004 - Revision: 3.1
APPLIES TO
  • Microsoft Visual Basic 5.0 Learning Edition
  • Microsoft Visual Basic 6.0 Learning Edition
  • Microsoft Visual Basic 5.0 Professional Edition
  • Microsoft Visual Basic 6.0 Professional Edition
  • Microsoft Visual Basic 5.0 Enterprise Edition
  • Microsoft Visual Basic 6.0 Enterprise Edition
  • Microsoft Visual Basic 4.0 Standard Edition
  • Microsoft Visual Basic 4.0 Professional Edition
  • Microsoft Visual Basic 4.0 32-Bit Enterprise Edition
Keywords: 
kbhowto kbapi KB154009

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