Default App

proc _defaultApp {extension} {
  # Find the name of the default application for a given file extension.
  # This procedure searches the "HKEY_CLASSES_ROOT" key in the Windows registry.
 
	package require registry
 
	if {[catch {set fileType [registry get "HKEY_CLASSES_ROOT\\$extension" ""]} ]} {
		puts "There is no default application assigned to '${extension}' files."
		return 0
	} else {
	  if {[catch {set defaultExe [registry get "HKEY_CLASSES_ROOT\\${fileType}\\shell\\open\\command" ""]} ]} {
	    puts "The default executable name for '${extension}' is not defined in the registry."
	    return 0
	  } else {
	    return $defaultExe
	  }
	}
}