Re: [ctypes-users] [Tutor] ctypes wintypes

[Michael C <mys...@gm...>]

like this?

buffer = ctypes.byref(ctypes.create_string_buffer(4))

On Fri, Oct 6, 2017 at 1:55 PM, eryk sun <er...@gm...> wrote:

> On Fri, Oct 6, 2017 at 9:12 PM, Michael C
> <mys...@gm...> wrote:
> >
> > How do I create a buffer, or rather, is a buffer just a variable?
>
> A buffer is a block of memory for an I/O operation. For example, if
> you need to read a 4-byte (32-bit) integer at an address in another
> process, the 'buffer' could be ctypes.c_int32(). In general, to read
> an arbitrary-sized block of memory, use ctypes.create_string_buffer()
> to create a char array.
>
> > How do I create a pointer to it?
>
> Pass it byref().
>
> > print('mbi.State: ',mbi.State)
>
> Check whether mbi.State is MEM_COMMIT before trying to read it. If
> it's MEM_FREE or MEM_RESERVE, then ReadProcessMemory will fail.
>
> > buffer = ctypes.create_string_buffer(4)
> > bufferSize = (ctypes.sizeof(buffer))
> >
> > ReadProcessMemory = Kernel32.ReadProcessMemory
> >
> > if ReadProcessMemory(Process, ctypes.byref(mbi), buffer, bufferSize,
> None):
> >         print('buffer is: ',buffer)
> > else:
> >         print('something is wrong')
>
> Don't print "something is wrong". You're capturing the thread's last
> error value, so use it to raise an informative exception. For example:
>
>     if not success:
>         raise ctypes.WinError(ctypes.get_last_error())
>