[BGL] setting a breakpoint in an algorithm visitor

From: Chris Russell (cdr_at_[hidden])
Date: 2002-09-16 11:31:43

p.156 of the BGL book: "... visitors are passed by value..."

I was attempting to set a breakpoint in a visitor event handler (that I know
is executing) but the breakpoint is seemingly ignored by my debugger. This
is because the visitor I construct and subsequently pass to the algorithm is
not the object that is actually dispatched by the algorithm. Correct? Using
the Intel compiler under MS DevStudio 6 on Windows, I inserted a
::DebugBreak() (asm int 3) into the visitor and *do* hit that but only have
assembly language and not source to step through at that point.

Why are visitors passed to algorithms by value? Any suggestions for
debugging visitor code at the C++ source level and not in assembly?

- Regards
Chris