Library /sys$common/syshlp/dbg$help.hlb DEBUG, SHOW, TASK, Qualifiers, /CALLS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /CALLS[=n]

    Does a SHOW CALLS command for each task selected for display.
    This identifies the currently active routine calls (the call
    stack) for a task.