address-expression

    Specifies an address expression (a program location) at which
    a breakpoint is to be set. With high-level languages, this
    is typically a line number, a routine name, or a label, and
    can include a path name to specify the entity uniquely. More
    generally, an address expression can also be a memory address or
    a register and can be composed of numbers (offsets) and symbols,
    as well as one or more operators, operands, or delimiters. For
    information about the operators that you can use in address
    expressions, see the Address_Expressions help topic.

    Do not specify the asterisk (*)  wildcard character. Do not
    specify an address expression with any of the following
    qualifiers:

       /ACTIVATING
       /BRANCH
       /CALL
       /EXCEPTION
       /HANDLER
       /INSTRUCTION
       /INTO
       /LINE
       /OVER
       /[NO]SHARE
       /[NO]SYSTEM
       /SYSEMULATE (Alpha only)
       /TERMINATING
       /UNALIGNED_DATA (Alpha and Integrity servers only)

    The /MODIFY and /RETURN qualifiers are used with specific kinds
    of address expressions.

    If you specify a memory address or an address expression whose
    value is not a symbolic location, check (with the EXAMINE
    command) that an instruction actually begins at the byte of
    memory so indicated. If an instruction does not begin at this
    byte, a run-time error can occur when an instruction including
    that byte is executed. When you set a breakpoint by specifying
    an address expression whose value is not a symbolic location, the
    debugger does not verify that the location specified marks the
    beginning of an instruction.

 conditional-expression

    Specifies a conditional expression in the currently set
    language that is to be evaluated whenever execution reaches the
    breakpoint. (The debugger checks the syntax of the expressions in
    the WHEN clause when execution reaches the breakpoint, not when
    the breakpoint is set.) If the expression is true, the debugger
    reports that a breakpoint has been triggered. If an action (DO
    clause) is associated with the breakpoint, it will occur at this
    time. If the expression is false, a report is not issued, the
    commands specified by the DO clause (if one was specified) are
    not executed, and program execution is continued.

 command

    Specifies a debugger command to be executed as part of the DO
    clause when break action is taken. The debugger checks the syntax
    of the commands in a DO clause when it executes the DO clause,
    not when the breakpoint is set.