Library /sys$common/syshlp/pca$help.hlb CANCEL, EVENT, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The CANCEL EVENT Collector command cancels the collection of
    event markers for a specified event when the specified program
    locations associated with that event are executed. Event markers
    for the event-name event are thus not recorded in the performance
    data file when these program locations are executed. If you
    specify an event-name without a program location, then all
    program locations associated with the event-name are canceled.