On 5 Des, 10:13, Carl Banks <pavlovevide...@gmail.com> wrote: > Is there a way to get the pointer to an array offset in ctypes. > Example, say I define an array like so: > > xfer = (c_char*bufsize)() > > How would I get a pointer to then nth byte (equivalient of &xfer[n])? > I guess I would have expected xfer+n to work, but it doesn't.
See: http://bugs.python.org/issue6259 For now, we can still work with char* by casting them to an integer: >>> from ctypes import * >>> bufsize = 1024 >>> xfer = (c_char*bufsize)() # cast to pointer >>> ptr = cast(xfer, POINTER(c_char)) # obtain address >>> addressof(xfer) 36279232 >>> addressof(ptr) 45151576 >>> addressof(ptr.contents) 36279232 # add offset to pointer >>> cast(addressof(ptr.contents)+10,POINTER(c_char)) <ctypes.LP_c_char object at 0x02B0F580> >>> cast(addressof(xfer)+10,POINTER(c_char)) <ctypes.LP_c_char object at 0x02B0FDA0> # byref also takes an offset >>> byref(xfer,0) <cparam 'P' (022993C0)> >>> byref(xfer,10) <cparam 'P' (022993CA)> -- http://mail.python.org/mailman/listinfo/python-list
