ExtractTemporaryFile

procedure ExtractTemporaryFile(const FileName: String);

Extracts the specified file from the [Files] section to a temporary directory. To find the location of the temporary directory use ExpandConstant('{tmp}').

The extracted files are automatically deleted when Setup exits.

An exception will be raised if the file wasn't extracted successfully, if the file wasn't found, or if the file was found but couldn't be processed because of its 'MinVersion' and/or 'OnlyBelowVersion' parameters.

Use 'Flags: dontcopy' in the [Files] section to tell Setup to skip the file during the normal file copying stage.

[Files]
Source: "Readme.txt"; Flags: dontcopy

[Code]
function InitializeSetup: Boolean;
var
  S: String;
begin
  // Show the contents of Readme.txt in a message box
  ExtractTemporaryFile('Readme.txt');
  if LoadStringFromFile(ExpandConstant('{tmp}\Readme.txt'), S) then
  begin
    MsgBox(S, mbInformation, MB_OK);
  end;

  Result := True;
end;