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

    Specifies that the debugger is to monitor a nonstatic variable
    by tracing instructions only within the defining routine, not
    within a routine that is called by the defining routine. As a
    result, the debugger executes a called routine at normal speed
    and resumes tracing instructions only when execution returns
    to the defining routine. The SET WATCH/OVER command provides
    faster execution than SET WATCH/INTO; but if a called routine
    modifies the watched variable, execution is interrupted only upon
    returning to the defining routine. When you set watchpoints on
    nonstatic variables, SET WATCH/OVER is the default.