How to know a file was written successfully

[Docfxit]

I am trying to write to the hosts file.  If the hosts file is read only this script works great.  If the hosts file is not read only it gets written to twice. 

I think I have two problems.

1.  When the first filewrite happens the script doesn't recognize it was written to successfully.

2.  On the second filewrite the file needs to be open before the write.  I don't understand why the file isn't open already.  Why does it need to be open again?

$strHost = @SystemDir & "\drivers\etc\hosts"
            $tcpIP = "192.168.254.254"
            $sWhat = "AnyDomain"
           
                       
$hFile = FileOpen($strHost, 1) 
            FileWrite($hFile, @LF & $tcpIP & " " & $sWhat)
            If @error = 1 Then
                MsgBox($MB_TOPMOST, 'TestBox 3', "Host file was written successfully  " & "@error = " & @error & @CRLF & $strHost)
            Else
                If Not FileSetAttrib($strHost, "-R") Then
                    MsgBox($MB_TOPMOST, 'TestBox 3', "After Host file write was read only " & "@error = " & @error & @CRLF & $strHost)
                EndIf
                $hFile = FileOpen($strHost, 1)  ;  I don't understand why the file needs to be open again.  It wasn't closed
                FileWrite($hFile, @LF & $tcpIP & " " & $sWhat)
                FileSetAttrib($strHost, "+R")
            EndIf
            FileClose($hFile)

Thank you,

Docfxit

Edited August 16, 2014 by Docfxit

[BrewManNH]

You're checking @error to see if it's 1 or not, you should be checking whether FileWrite returns 1 or not, not @error. So if it writes to the file successfully, @error won't equal 1, so it writes it again.

FileWrite($hFile, @LF & $tcpIP & " " & $sWhat)
If @error = 1 Then
    MsgBox(0x40000, 'TestBox 3', "Host file was written successfully  " & "@error = " & @error & @CRLF & $strHost)
Else

[jchd]

1/ You are confusing @error and return value.

2/ Can you really change a file attribute (especially RO) with that file currently open for write?

[Docfxit]

 

You're checking @error to see if it's 1 or not, you should be checking whether FileWrite returns 1 or not, not @error. So if it writes to the file successfully, @error won't equal 1, so it writes it again.

FileWrite($hFile, @LF & $tcpIP & " " & $sWhat)
If @error = 1 Then
    MsgBox($MB_TOPMOST, 'TestBox 3', "Host file was written successfully  " & "@error = " & @error & @CRLF & $strHost)
Else

 

I changed the code to:

$filewritten = FileWrite($hFile, @LF & $tcpIP & " " & $sWhat)
            If $filewritten = 1 Then
                MsgBox($MB_TOPMOST, 'TestBox 3', "Host file was written  " & "@error = " & @error & @CRLF & $strHost)
            Else

And it works great now.  Thank you very much for pointing me in the right direction.

Docfxit

Edited August 16, 2014 by Docfxit

[Docfxit]

1/ You are confusing @error and return value.

2/ Can you really change a file attribute (especially RO) with that file currently open for write?

 

1.  Thanks for letting me know.  I wish there was an example in the help file to show that.

2.  It seems to work.  I can certainly move the file attribute after the close.

Thank you very much,

Docfxit

[water]

Magic Numbers in your MsgBox statement? If Guinness sees this, then ...

[jchd]

2/ Remember your own question: Why does it need to be open again?

My answer was that changing the file attibute forcibly closes the file, else the OS would be self-contradictory (writing to a RO file would work). Hence the need to reopen after that.

[Docfxit]

2/ Remember your own question: Why does it need to be open again?

My answer was that changing the file attibute forcibly closes the file, else the OS would be self-contradictory (writing to a RO file would work). Hence the need to reopen after that.

 

Oh Great.  Thank you for clarifying that.

Thank you,

Docfxit

[Docfxit]

Magic Numbers in your MsgBox statement? If Guinness sees this, then ...

 

It sounds like he might be upset? 

What are Magic Numbers?

Why shouldn't they be used?

I'd like to fix it before he sees it.  I'd just like to know what I am fixing and why.  I don't want anyone to get upset.

Thanks for the heads up.

Docfxit

[water]

Just a joke

But it is preferred to use the Constant Names as described in the help file for MsgBox.

Magic Numbers are descriibed as "Unique values with unexplained meaning ...". Using Constants will help you to be able to read your code in the future more easily.

Just replace 0x40000 with $MB_TOPMOST.

Edited August 16, 2014 by water

[jchd]

Docfxit,

water is right: don't do that.

guinness has a record of launching ICBMs against people who persist using magic numbers, so if your IP can be located close enough to your door you're putting your familly (and neighbours) at high risk.

Fortunately my ISP provide me with IPs that can only be located at either 250 or 430 km from where I actually live depending on how you use traceroute tools, so I'm pretty safe for now. I feel sorry for many people wounded or killed nearby the big hubs in my network...

[Docfxit]

Just a joke

But it is preferred to use the Constant Names as described in the help file for MsgBox.

Magic Numbers are descriibed as "Unique values with unexplained meaning ...". Using Constants will help you to be able to read your code in the future more easily.

Just replace 0x40000 with $MB_TOPMOST.

 

Thank you for letting me know.

I have replaced what I could in this thread and all my scripts.

I'm always happy to learn better ways of doing things.

It always amazes me of how many ways there are of doing things.

And how many ways a person can get in trouble.

All joking aside

Thanks,

Docfxit

[water]

Seems we have another satisfied customer here

[Docfxit]

Docfxit,

water is right: don't do that.

guinness has a record of launching ICBMs against people who persist using magic numbers, so if your IP can be located close enough to your door you're putting your familly (and neighbours) at high risk.

Fortunately my ISP provide me with IPs that can only be located at either 250 or 430 km from where I actually live depending on how you use traceroute tools, so I'm pretty safe for now. I feel sorry for many people wounded or killed nearby the big hubs in my network...

 

Amazon is currently testing a new delivery system with drones that look like helicopters. They deliver packages to your front door step.

What's your address?

Docfxit

PS:  I hope you got a laugh out of this.

Edited August 16, 2014 by Docfxit