#319 Application running while uninstallation

[gapchoos]

How to check and return a true variable if the Application is running before the uninstallation process?

set program <%AppName%>.exe
foreach pid $pids {
set value expr {[llength [twapi::get_process_ids -name $program]] > 0}
return $value

}

The above script was tried. But it doesnot return any values. How to solve this issue? I am new to TCL Scripting. SO thereby expecting a detailed solution.