Library /sys$common/syshlp/dbg$help.hlb DEBUG, New Features, EXAMINE/VARIANT Command  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The EXAMINE command has a new /VARIANT qualifier that enables
    the debugger to display the correct item when it encounters an
    anonymous variant.

    In a C program, a union contains members, only one of which is
    valid at any one time. When displaying a union, the debugger does
    not know which member is currently valid. In a PASCAL program,
    a record with a variant part contains variants, only one of
    which is valid at any one time. When displaying a record with an
    anonymous variant part, the debugger does not know which variant
    is currently valid, and displays all variants by default.

    You can use the /VARIANT qualifier to select which member of
    a union (C program) or anonymous variant (PASCAL program) to
    display. The format is as follows:

     DBG> EXAMINE /VARIANT=var-selector address-exp

     DBG> EXAMINE /VARIANT=(var-selector,...)  address-exp

    The variant selector var-selector specifies a name, a
    discriminant (PASCAL only), or a position; that is, one of the
    following:

    o  NAME = name-string

    o  DISCRIMINANT = expression

    o  POSITION = expression

    For more information, see the EXAMINE topic.