in reply to Re^4: Win32::API->new( ReadProcessMemory ) not working how I'd expect
in thread dumping the memory of a foreign win32 pid from perl
... since CreateToolhelp32Snapshot() seems to take a "snapshot," so you don't have to worry about state changes ...
Well sure. You ask for a snapshot and get it. As you process that snapshot, you are told there is a read/write chunk of memory 39046kb long starting at 0x00x6580000. So you go to read that with ReadProcessMemory(), but in the meantime, the process called VirtualFree() and oh, sorry all gone. Or it dynamically loads a new DLL, or releases an old one, or creates or destroys a thread. Or just reaches the end of its program and terminates.
A snapshot is just that, a moment in time. Self-consistant at that moment in time, but otherwise still a static representation of a complex, running process, subject to change. Suspend the process before you get your snapshot and nothing will change until you resume it.
(It would seem this isn't very perl related.)
Hm. It can all be done from Perl, and to a Perl process. So it is at least as relevant as all the many, many posts here on how to explore the /dev/proc/... virtual filespaces on *nix, and nobody bats an eye at questions about or answers that detail its use.
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