fcl-registry

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Revision as of 07:47, 21 July 2014 by BigChimp (talk | contribs) (64 bit and 32 bit registry)
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fcl-registry is an FCL unit that provides access to the Windows registry.

Registry terms

RootKey: registry hive where you want to start accessing the registry. Examples: HKEY_LOCAL_MACHINE, HKEY_CURRENT_USER

Key: the path to the "directory" that contains individual data. This is a bit counter-intuitive but a holdover from compatibility with earlier versions of the registry.

Name/value: the actual name/value pairs in the Key "directory". Each key can have a default value, whose name is (an empty string.

Example

Example that tries to get a value:

uses ... registry...

var
  CompileCommand: string='';
  Registry: TRegistry;
begin
  Registry := TRegistry.Create;
  try
    // Navigate to proper "directory":
    Registry.RootKey := HKEY_LOCAL_MACHINE;
    if Registry.OpenKeyReadOnly('\SOFTWARE\Classes\InnoSetupScriptFile\shell\Compile\Command') then
      CompileCommand:=Registry.ReadString(''); //read the value of the default name
  finally
    Registry.Free;
  end;
end;

Accessing 64 bit and 32 bit registry views

If you have 64 bit Windows, the registry is split up into a 64 bit and 32 bit (compatibility) part. By default, if you run a 32 bit process, you see the 32 bit part; if you run a 64 bit application, you see the 64 bit part.

You can also access the 32 bit part from 64 bit applications and vice versa. From MSDN: http://msdn.microsoft.com/en-us/library/windows/desktop/aa384129%28v=vs.85%29.aspx

  • KEY_WOW64_64KEY (value $0100): Access a 64-bit key from either a 32-bit or 64-bit application.
  • KEY_WOW64_32KEY (value $0200): Access a 32-bit key from either a 32-bit or 64-bit application.

See also

Packages List