GDB under emacs can't deal with source code frame

[xf . lotus]

Hi,

    I try to use gdb under emacs to debug source code. According to
the manual, after starting gdb under emacs, there should be a arrow in
the left fringe indicating the current executing line. But, in my
experience, this is not the case. Although the source frame appear,
there is not the arrow at all. The environment: winxp + emacs-22.3-
win, and the varibles gdb-many-windows and gdb-show-main are non-nil.


Any suggestion?