title: Inno Setup FileCopy using {app} variable as part of directory
body: <p>How can i use variables in Inno Setup <code>FileCopy</code> command in the <code>[Code]</code> section?</p>
  
  <pre><code>`FileCopy(ExpandConstant('{app}\Backup\config.ini'),ExpandConstant('{app}\bin\config.ini'),False);`
  </code></pre>
  
  <p>This is what i am using but not seem to work... Im using this inside a Procedure... And calling this Procedure using <code>Afterinstall:</code> in <code>[Files]</code> section.</p>
  
  <pre><code>[Files]
  Source: "C:\dev\bin\config.ini"; DestDir: "{app}\bin\"; Flags: ignoreversion recursesubdirs createallsubdirs; Tasks: Steam; AfterInstall: RunOtherInstaller;
  
  
  [Code]
  procedure RunOtherInstaller;
      var 
      Path: String;
      ErrorCode: Integer;
      begin
        if (RegQueryStringValue(HKEY_LOCAL_MACHINE, 'Software\Valve\Steam', 'InstallPath', Path)) and (FileExists(Path + '\Steam.exe')) then 
        begin
          //ShellExec('', ExpandConstant('"' + Path + '\Steam.exe' + '"'), 'steam://','', SW_SHOW, ewNoWait, ErrorCode);
          Exec(ExpandConstant(Path + '\Steam.exe'), 'steam://', '', SW_SHOWNORMAL, ewNoWait, ErrorCode)
        end
        else
        begin
          MsgBox('Steam not found', mbError, MB_OK);
          FileCopy(ExpandConstant('{app}\Backup\config.ini'),ExpandConstant('{app}\bin\config.ini'),False);
          end
      end;
  </code></pre>