The Zoo kernel provides the option to store a status message in shared memory along with the status value (i.e. the progress in percent), see this ticket: ​http://zoo-project.org/trac/ticket/81. However, the current implementation of updateStatus (service_internal.c, revision # 452) does not check if getMapFromMaps(conf,"lenv","message") returns NULL. A segmentation fault occurs (line 115) if a message value has not been set in the service code before a call to updateStatus:

// OK:
setMapInMaps( conf, "lenv", "status", "99" );
setMapInMaps( conf, "lenv", "message", "Progress: 99%" );
updateStatus( conf );

// Segmentation fault:
setMapInMaps( conf, "lenv", "status", "99" );	
updateStatus( conf ); 

(Tested on a Window 7 system.)