FileRead - continuously updated file

[DeltaRocked]

Hi,

I have been trying to read a file which is being continuously written by another process. At some point, the FileReadLine reaches EOF and the Second Process appends the file .

When using Filereadline and FileSetPos / FilegetPos , I am unable to go past the last FileReadLine. I have to always close the file and reopen it , set the file pointer position and then continue reading till EOF.

 

#include <FileConstants.au3>
Local $hFile, $sPos, $neof
$hFile = FileOpen('abc.txt', 0)
While 1
    $line = FileReadLine($hFile)
    If (@error = -1) Then
        $sPos = FileGetPos($hFile)
        ConsoleWrite(" ---- " & $sPos & ' ---- ' & @CRLF)
        FileClose($hFile)
        $hFile = FileOpen('abc.txt', 0)
        FileSetPos($hFile, $sPos, $FILE_BEGIN)
        $neof = 1
    Else
        $neof = 0
    EndIf
    If ($neof = 0) Then
        ConsoleWrite($line & @CRLF)
    EndIf
WEnd

looping.bat
rem -------------------
dir /s >> abc.txt
rem -------------------

At Command Prompt : looping.bat

How do I ensure that I can read the file as and when it gets updated.

[UPDATE]

I believe its done. but may require some fine tuning.

#include <FileConstants.au3>
Local $hFile, $sPos, $neof, $sFilePreviousPos_1, $sFileCurrentPos_1, $sFilePreviousPos, $error

$hFile = FileOpen('abc.txt', 0)
$sFileCurrentPos = FileGetPos($hFile)
While 1
    $line = FileReadLine($hFile)
    $error = @error
    $sFilePreviousPos = $sFileCurrentPos
    $sFileCurrentPos = FileGetPos($hFile)
    If ($error = -1) Then
        FileSetPos($hFile, $sFilePreviousPos, $FILE_BEGIN)
        $neof = 1
    Else
        $neof = 0
    EndIf
    If ($neof = 0) Then
            ConsoleWrite($line & @CRLF)
    EndIf
WEnd

 

 

Thanks in Advance.

 

Edited May 5, 2018 by DeltaRocked

[bernd670]

Hello,

not so complicated, FileGetPos and FileSetPos is only needed if the same handle wants to read and write the file. Batch and AutoIt use different handles.

Try this:

While Not FileExists("abc.txt")
    Sleep(1000)
WEnd

$hFile = FileOpen("abc.txt", 0)

While 1
    $Line = FileReadLine($hFile)
    If Not @error Then ConsoleWrite($Line & @CRLF)
WEnd

 

Edited May 5, 2018 by bernd670

[jchd]

Regular files offer zero guarantee for ACID properties, unless locks are set/released so that file integrity is maintained among non-cooperating threads/processes.