Read empty reg key &/or default reg name.

[caramen]

Well let's say first i got the jargon with registry french words. But i am not sure about english ones.

I would like to improve my registry knowledge.

 

I noticed i dont know how to check an existing key when she got no value inside it. I know with what i am saying now there is two cases possible but mine is this one :

So if you can give me the correct english names for theses...

I would say for the :

Black square : KEY

Blue square : Value Name

Reg square : Value Type

Now my issue.

If i have a value name: Value1 with or without data set in it. I know how to check it. I just regread it and play with the return.

But in this case i dont know how to get the "par défaut" value name if i try to regread it i am not successing. I dont know how to manage the return of it. I dont even now if this "par défaut" value name is existing or just a "virtual" data. or somthing.

 

 

The goal is: Sometime I need to check the existence of an app(that mean the existence of the key) on a laptop but I always switch my method when i face this. But i like using the registry so if i can bypass that issue that would be cool .

Edited December 28, 2018 by caramen

[kamiquasi]

If I'm reading this right, you're just trying to see if KEY exists, and don't necessarily care about the value of '(Default)'?

If that is the case, you should check the @error value after using RegRead.  Instead of specifying a value name, you can specify "" (which is what '(Default)' is referenced as, regardless of locale/language).

; Check if 'UserConfig' for 'MySoftware' exists and, if so, parse its '(Default)' value.
Local $defaultValue = RegRead("HKCU\Software\MySoftware\UserConfig","")
Local $errorRegRead = @error
ConsoleWrite("Error: "&$errorRegRead&@CRLF)
If ($errorRegRead == 0) Then
    ConsoleWrite("Value of (Default): "&$defaultValue&@CRLF)
ElseIf ($errorRegRead > 0) Then
    ConsoleWrite("Key does not exist OR key could not be accessed OR key trunk could not be accessed"&@CRLF)
ElseIf ($errorRegRead < 0) Then
    ConsoleWrite("Value name does not exist OR value s not set OR value can not be accessed"&@CRLF)
EndIf

If you do need to check for a specific value of '(Default)', you can perform the usual tests on $defaultValue to see if it's blank or some value when the @error is 0 (zero).

The RegRead help has all this info, but this might make it easier to understand

[Subz]

I use the following udf, and RegKeyExists function as @kamiquasi points out you can test by using the @error return value.

Func RegKeyExists($s_key)
    _RegRead($s_key, "") ; try to read default value
    Switch @error
        Case 1, 2
            ; invalid root key | failed to open key
            Return SetError(@error, 0, 0)
        Case Else
            ; key exists
            Return SetError(0, 0, 1)
    EndSwitch

 

[caramen]

Thanks guys yeah i was pretty stupid... It is just when we do somthing too much time we sometime forget to do the easyer thing first.... Totaly forget about using the @error flag... So obvius after reading it...

 

Happy new year.

[Subz]

No problem, happy new year to you as well.

[caramen]

On 28/12/2018 at 4:19 PM, kamiquasi said:

If you do need to check for a specific value of '(Default)', you can perform the usual tests on $defaultValue to see if it's blank or some value when the @error is 0 (zero).

The RegRead help has all this info, but this might make it easier to understand

Or even @Subz When i try the following. I am not getting the defaut value i haven't the administrator right on this win session but i am reading current user registry so... 

test()



Func test()
   $Regread = RegRead ( "HKEY_CURRENT_USER\Control Panel\Accessibility\On","")
   $Erreur = @extended
   If $Erreur = 1 Then MsgBox (0,"Erreur","Erreur 1 = unable to open requested key")
   If $Erreur = 2 Then MsgBox (0,"Erreur","Erreur 2 = unable to open requested main key")
   If $Erreur = 3 Then MsgBox (0,"Erreur","Erreur 3 = unable to remote connect to the registry")
   If $Erreur = -1 Then MsgBox (0,"Erreur","Erreur -1 = unable to open requested value")
   If $Erreur = -2 Then MsgBox (0,"Erreur","Erreur -2 = value type not supported")
    
   If $Erreur = 0 Then MsgBox (0,"Registre","Clef = "& $Regread )
   
    $Erreur = 0
EndFunc

Should post that with a switch to respect the exemple but well it's same...

This is my return :

Erreur 2 = unable to open requested main key

This is my registry :

Btw if i read Locale it is working.

Edited January 2, 2019 by caramen

[Subz]

It should be:

$Erreur = @error

@extended returns the registry type i.e. REG_SZ, REG_DWORD etc...

[caramen]

I dont know why it is working then .

 

But I still cannot read this default value .

What is it ? My syntax maybe?

 

[Subz]

(Default) is not an actual value and by default doesn't hold any data, you can see in your screenshot that (Default) has a value that has not been set.  As mentioned above, if @error = 1 or 2 than the key doesn't exist, -1 or -2 result means the key exists, but their is an issue with the value i.e. it hasn't been set.

[caramen]

@Subz But the help file saying :

To access the (Default) value use "" (an empty string) for the valuename.

@Melba23 Does i am in special case for the second time ? Does the help file is again not updated ?

Edited January 3, 2019 by caramen

[Subz]

@caramen The help file is correct to access (Default) you need to use "", as mentioned (Default) does not normally have a value, I'm not sure what you're expecting to be returned, RegRead will return a blank value whether or not the key exists, which is why its better to use @error to determine if the key exists".  Example \Off key below shouldn't exist, \On Key should exist, but blank value, and \Au3Info.exe should return the path to Au3Info.exe as the (Default) vaule has been set.

ConsoleWrite(_RegKeyExists("HKCU\Control Panel\Accessibility\Off") & @CRLF)
ConsoleWrite(_RegKeyExists("HKCU\Control Panel\Accessibility\On") & @CRLF)
ConsoleWrite(_RegKeyExists("HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\Au3Info.exe") & @CRLF)

Func _RegKeyExists($_sRegKey)
    Local $sDefault = RegRead($_sRegKey, "") ;~ Try to read default value
    Switch @error
        Case 1, 2
            ;~ Unable to open requested key | Unable to open requested main key
            Return SetError(@error, 0, 'Error: Registry Key: "' & $_sRegKey & '" does not exist.')
        Case Else
            ; Registry Key Exists | Return (Default) value
            Return SetError(0, 0, $sDefault)
    EndSwitch
EndFunc

 

[caramen]

@Subz Obviusly I dont understand somthing.

But I have to figure out what is it.

It is this :

This sample :

ConsoleWrite(RegRead ("HKCU\Control Panel\Accessibility\On","") & @CRLF)
ConsoleWrite(RegRead ("HKCU\Control Panel\Accessibility\Off", "") & @CRLF)

And this sample :

ConsoleWrite(_RegKeyExists("HKCU\Control Panel\Accessibility\Off") & @CRLF)
ConsoleWrite(_RegKeyExists("HKCU\Control Panel\Accessibility\On") & @CRLF)

Func _RegKeyExists($_sRegKey)
    Local $sDefault = RegRead($_sRegKey, "") ;~ Try to read default value
    Switch @error
        Case 1, 2
            ;~ Unable to open requested key | Unable to open requested main key
            Return SetError(@error, 0, 'Error: Registry Key: "' & $_sRegKey & '" does not exist.')
        Case Else
            ; Registry Key Exists | Return (Default) value
            Return SetError(0, 0, $sDefault)
    EndSwitch
EndFunc

Are same. The function does not change there is just an error checking added.

But why :

;This:
ConsoleWrite(_RegKeyExists("HKCU\Control Panel\Accessibility\On") & @CRLF)
;And This:
ConsoleWrite(RegRead ("HKCU\Control Panel\Accessibility\On","") & @CRLF)

Are not returning the same thing ?

;This Return an empty string:
ConsoleWrite(_RegKeyExists("HKCU\Control Panel\Accessibility\On") & @CRLF)
;And This Return an error: (But an empty string in the console)(Corect me if i am false it is becose the error is here BUT the @CRLF = Empty string)
ConsoleWrite(RegRead ("HKCU\Control Panel\Accessibility\On","") & @CRLF)

 

Edited January 3, 2019 by caramen

[Subz]

What error is it returning?  It's returning a blank string for me.

[caramen]

(Corect me if i am false it is becose the error is here BUT the @CRLF = Empty string)

 

Erreur 2 = unable to open requested main key

Edited January 3, 2019 by caramen

[caramen]

I did a mistake. It is error -1. I think i got it now.

Edited January 3, 2019 by caramen

[Subz]

As I've mentioned, (Default) normally doesn't have a value which is why value reads (value not set) or (valeur non definie) so it will return -1, if @error = 1 or 2 then the key doesn't exist.

(Corect me if i am false it is becose the error is here BUT the @CRLF = Empty string)

RegRead will return an empty string "" (not @CRLF) whether or not the key or value exists.  However most people would check to see if a value exists as keys don't really have any value.  As an example if I was going to roll our AutoIt 3.3.14.5 I'd use something like the following:
nb: Find examples are easier to explain  

;~ Check if AutoIt 3.3.14.5 is installed
Local $bAutoItv3_3_14_5 = RegRead ("HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\AutoItv3", "DisplayVersion") = "3.3.14.5" ? True : False
;~ Install AutoIt 3.3.14.5 if not found
If $bAutoItv3_3_14_5 = False Then RunWait(@ScriptDir & "\autoit-v3-setup.exe -s")

 

[caramen]

1 hour ago, Subz said:

(Corect me if i am false it is becose the error is here BUT the @CRLF = Empty string)

Yeah this was true with my mistake but false in the correct case.

Edited January 3, 2019 by caramen

[caramen]

Hey @Subz Thank you, you just learned me somthing.

I never seen that kind of script. With "?"