Need help with WinAPI

[Martin Francom]

Can someone give me an PB example of how to use the WinAPI function CompareFileTime ?

I want to compare two files and find out which is older. I have not been able to get the syntax right for the API function.

[Chris Holbrook]

It was mentioned here, if that helps...

[Martin Francom]

It was mentioned here, if that helps...

Yes, I saw that. But the actual PB call was not stated.

This is what I have, maybe if someone can help clarify the variables....

Declare Function CompareFileTime Lib "kernel32" ( _
lpFileTime1 As FILETIME, _
lpFileTime2 As FILETIME _
) As Long

What do I put in lpFileTime1 and lpFileTime2 ?

And what is FILETIME ?

This result should be:

-1 lpFileTime1 is smaller than lpFileTime2
0 lpFileTime1 is equal to lpFileTime2
+1 lpFileTime1 is larger than lpFileTime2

I just don't know what I shoulld be using for the variables?

[Clay Clear]

Martin,

There is nothing wrong with using PB's QUAD variables to do that, and if you do that, you will instantly have the information you need. But you would have to explicitly use BYVAL VARTPTR with the QUAD variables, because of the PB prototype in WIN32API.

In re (it's been a long time since I had to look up the prototype, so this could be worng):

GetFileTimes <filername>, BYVAL VARPTR(quad#1>, BYVAL VARTPTR(quad # 2), BYVAL VARPTR(quad

[Chris Holbrook]

MSDN filetime http://msdn.microsoft.com/en-us/libr...8VS.85%29.aspx

[Dale Yarker]

Yes, I saw that. But the actual PB call was not stated.

This is what I have, maybe if someone can help clarify the variables....

Declare Function CompareFileTime Lib "kernel32" ( _
lpFileTime1 As FILETIME, _
lpFileTime2 As FILETIME _
) As Long

What do I put in lpFileTime1 and lpFileTime2 ?

And what is FILETIME ?

This result should be:

-1 lpFileTime1 is smaller than lpFileTime2
0 lpFileTime1 is equal to lpFileTime2
+1 lpFileTime1 is larger than lpFileTime2

I just don't know what I shoulld be using for the variables?

A FILETIME is a 64bit TYPE containing the date and time in 100nSec units
since 1 Jan 1601 (UTC). Can be used for calculations and comparisions
on Dates/Times other than files.

What you put lpFileTime1 and lpFileTime2 is one of three times
associated with a file (see example code).

#include "Win32API.inc"
function CompFileTimes(FileName1 as string, FileName2 as string) as long
  local nFile1, nFile2 as dword 'PB file number
  local hFile1, hFile2 as dword 'Windows handle for file
  local ErrNum as long
  local FT1_Create, FT1_LastAccess, FT1_LastWrite as FileTime
  local FT2_Create, FT1_LastAccess, FT1_LastWrite as FileTime

  nFile1 = freefile
  open FileName1 for binary as #nFile1 'can be "for input", "for append,
  '{error checking left out}           '"for output" or "for random"
  nFile2 = freefile
  open FileName2 for binary as #nFile2
  '{error checking left out}
  hFile1 = fileattr(#nFile1, 2)
  hFile2 = fileattr(#nFile2, 2)
  ErrNum = GetFileTime hFile1, FT1_Create, FT1_LastAccess, _
                                         FT1_LastWrite as FileTime
  '{error checking left out}
  ErrNum = GetFileTime hFile2, FT1_Create, FT2_LastAccess, _
                                         FT2_LastWrite as FileTime
  '{error checking left out}
  function = CompareFileTime FT1_LastWrite, FT2_LastWrite
  close
#if 0 '-----------logical equiv of CompareFileTime ------
  if FT1_LastWrite > FT2_LastWrite then
    function = 1
  elseif FT1_LastWrite < FT2_LastWrite then
    function = -1
  else
    function = 0
  end if
#endif
end function

Have you looked msdn.microsoft.com ?

[Paul Squires]

This is what I use to check to see if one file is new than another.

First, get the FILETIME of each file:

Local diskFILETIME1, diskFILETIME1 As FILETIME
Local sFilename1 As ASCIIZ * %MAX_PATH
Local sFilename2 As ASCIIZ * %MAX_PATH

...
...
...

DTSignature sFilename1, diskFILETIME1
DTSignature sFilename2, diskFILETIME2


Next, do the comparison:

If CompareFileTime( diskFILETIME1, diskFILETIME1 ) <> 0 Then
..
..
..
End If

'//
'//  Determines the last update date/time of the specified file
'//  The time stamp, as its raw FILETIME API value (64-bit) ; 0 on error
'//  This function is purely to provide a way of telling when this value
'//  changes for a file ; turning the value found into a human-readable
'//  time is another matter altogether.
'//
Function DTSignature( ByRef zFileSpec As Asciiz, _
                      RETURN_FILETIME As FILETIME _
                      ) Export As Long

  Local hFile As Long
  Local uFind As WIN32_FIND_DATA

  'Locate the file...
  hFile = FindFirstFile( zFileSpec, uFind )

  If hFile Then
    Return_FILETIME = uFind.ftLastWriteTime
    FindClose hFile
  End If

End Function

[Martin Francom]

Dale & Paul,
Thank you. Your explanations have been most helpful. If you can indulge me and answer a couple additional questions.
Files have several dates: Date Created, Date modified, Date Accessed, and others. Which date do these routine use for making the comparison? I am hoping it's the date modified.

If one of the files on which the comparison is going to be made is downloaded first from the intenet, will that affect the date comparison?

[Paul Squires]

My code uses the last time the file was written to (uFind.ftLastWriteTime) so I guess it would be "Date Modified".

Check out:

http://msdn.microsoft.com/en-us/library/aa365740(VS.85).aspx

If one of the files on which the comparison is going to be made is downloaded first from the intenet, will that affect the date comparison?

Not sure about an answer for that question. Not sure if the file date/time stamp gets modified when a file is downloaded. I guess the easiest way is to test it.

[Dale Yarker]

Date Modified (LastWrite).

Internet - I think all three dates will be time of download. Dates for files inside a dot zip are preserved.

=============
added CLOSE in code in my previous post