This function sets the default root for any calls to PxHelpUrl. Once the default root is set, .html files can be referenced relative to the url_root path.
Gamma> PxHelpUrl("/usr/help/product/gamma/photon/PtBarGraph.html");
t <The PtBarGraph helpviewer page is displayed.>
Gamma> PxHelpUrlRoot("/usr/help/product/gamma/photon/");
t
Gamma> PxHelpUrlRoot("PtBarGraph.html");
t <The PtBarGraph helpviewer page is displayed.>
PxHelpQuit, PxHelpTopic, PxHelpTopicRoot, PxHelpTopicTree, PxHelpUrl
and in Photon documentation: PxHelpUrlRoot.