FILELEN() Function slow to update?

[Keith Elkin]

I'm having a strange problem using random file access and was wondering if
anyone is aware of why this might be happening. When I write new records to
the file, it seems to take a few seconds before the FILELEN() function to
update with the accurate length. As a test I did the following:

Sub test()
Dim inta As Integer

For inta = 1 To 5

Raffle.TicketsPurchased = inta
Put #20, inta, Raffle
Get #20, inta, Raffle
'Delay (2) Notice this is commented out)
intNumRows = FileLen(App.Path & "\herosraffle.dat") / Len(Raffle)
Say (Str(intNumRows) + " " + Str(Raffle.TicketsPurchased))
Next inta
End Sub
This gave me the following results

1 1
1 2
2 3
3 4
4 5
If I re-run the code with the 2 second delay added in I get

1 1
2 2
3 3
4 4
5 5
Why does it take so long for FILELEN() to update? Is there another way I
can check for how many records are in the file using a different command?
Adding a delay slows down the process this program is performing. Thanks in
advance,
-Keith

[Steve Gerrard]

"Keith Elkin" <ke***@keithelkin.com> wrote in message
news:d%*********************@news4.srv.hcvlny.cv.n et...

I'm having a strange problem using random file access and was wondering if anyone is aware of why this might be happening. When I write new records to the file, it seems to take a few seconds before the FILELEN() function to update with the accurate length. As a test I did the following:

Sub test()
Dim inta As Integer

For inta = 1 To 5

Raffle.TicketsPurchased = inta
Put #20, inta, Raffle
Get #20, inta, Raffle
'Delay (2) Notice this is commented out)
intNumRows = FileLen(App.Path & "\herosraffle.dat") / Len(Raffle)
Say (Str(intNumRows) + " " + Str(Raffle.TicketsPurchased))
Next inta
End Sub
This gave me the following results

1 1
1 2
2 3
3 4
4 5
If I re-run the code with the 2 second delay added in I get

1 1
2 2
3 3
4 4
5 5
Why does it take so long for FILELEN() to update? Is there another way I can check for how many records are in the file using a different command? Adding a delay slows down the process this program is performing. Thanks in advance,
-Keith

Use LOF(#) to get the length of an open file (in your case, LOF(20).
FileLen(Path) is for closed files. You also might want to use FreeFile
to get a file number, instead of using a hard coded value.

[Randy Birch]

Data written to disk is a buffered action, which Windows does when it can.

BTW, the proper formula for calculating the number of records in a random
access file, once it has been opened, is:

totalrecords = LOF(#hfile) \ Len(YourUDT)

Notice too that the division is Integer division, not Floating Point, as
there will never be a decimal.

And conversely, FYI, the next new record for a random access file is always
totalrecords + 1
--

Randy Birch
MVP Visual Basic
http://vbnet.mvps.org/
Please respond only to the newsgroups so all can benefit.

There's no place like 127.0.0.1
"Keith Elkin" <ke***@keithelkin.com> wrote in message
news:d%*********************@news4.srv.hcvlny.cv.n et...
: I'm having a strange problem using random file access and was wondering if
: anyone is aware of why this might be happening. When I write new records
to
: the file, it seems to take a few seconds before the FILELEN() function to
: update with the accurate length. As a test I did the following:
:
: Sub test()
: Dim inta As Integer
:
: For inta = 1 To 5
:
: Raffle.TicketsPurchased = inta
: Put #20, inta, Raffle
: Get #20, inta, Raffle
: 'Delay (2) Notice this is commented out)
: intNumRows = FileLen(App.Path & "\herosraffle.dat") / Len(Raffle)
: Say (Str(intNumRows) + " " + Str(Raffle.TicketsPurchased))
: Next inta
: End Sub
:
:
: This gave me the following results
:
: 1 1
: 1 2
: 2 3
: 3 4
: 4 5
:
:
: If I re-run the code with the 2 second delay added in I get
:
: 1 1
: 2 2
: 3 3
: 4 4
: 5 5
:
:
: Why does it take so long for FILELEN() to update? Is there another way I
: can check for how many records are in the file using a different command?
: Adding a delay slows down the process this program is performing. Thanks
in
: advance,
: -Keith
:
: