199   ViewerKind Viewer = VK_None;  in DisplayGraph()  local
201   if (!Viewer && S.TryFindProgram("open", ViewerPath))  in DisplayGraph()
202     Viewer = VK_OSXOpen;  in DisplayGraph()
204   if (!Viewer && S.TryFindProgram("gv", ViewerPath))  in DisplayGraph()
205     Viewer = VK_Ghostview;  in DisplayGraph()
206   if (!Viewer && S.TryFindProgram("xdg-open", ViewerPath))  in DisplayGraph()
207     Viewer = VK_XDGOpen;  in DisplayGraph()
209   if (!Viewer && S.TryFindProgram("cmd", ViewerPath)) {  in DisplayGraph()
210     Viewer = VK_CmdStart;  in DisplayGraph()
216   if (Viewer &&  in DisplayGraph()
220         Filename + (Viewer == VK_CmdStart ? ".pdf" : ".ps");  in DisplayGraph()
224     if (Viewer == VK_CmdStart)  in DisplayGraph()
246     switch (Viewer) {  in DisplayGraph()