https://manpages.ubuntu.com/manpages/xenial/man3/Ns_StopServer.3aolserver.html
Ubuntu Manpage: Ns_Main, Ns_StopServer, Ns_WaitForStartup - library procedures
ubuntumanpagensmainlibrary
https://www.ibm.com/support/pages/apar/PH39568
PH39568: STOPSERVER AND SERVERSTATUS FAILS TO WORK AFTER UPGRADING TO 9.0.5.8 AND 8.5.5.20
Details will be posted.
https://api.drupal.org/api/drupal/core%21tests%21Drupal%21BuildTests%21Framework%21BuildTestBase.php/function/BuildTestBase%3A%3AstopServer/10
function BuildTestBase::stopServer | Drupal API
functiondrupalapi