On 2007-11-20, xi4oyu <Evil.xi4oyu@gmail.com> wrote: > I wanna know why the gdb's 'attach' command can work? > In the virtual memory enviornment,Does it say that a program can't > direct 'invade' another's processs's space? Please tell me the > reason why gdb can do so... I think you just misunderstand the statement about virtual memory. Virtual memory is separate for each process, so the process may think that it's the only process in memory. But since the virtual memory is actually stored in RAM (or swap), then of course kernel has access to that memory and may provide such access to programs that need it. So no process can directly access the memory of another process, but some process may request from kernel indirect access to the memory of another process. -- Minds, like parachutes, function best when open