On Thu, Feb 28, 2013 at 10:27 AM, Paul Moore email@example.com wrote:
On 27 February 2013 23:18, Armin Rigo firstname.lastname@example.org wrote:
from cffi import FFI ffi = FFI() ffi.cdef(""" int MessageBox(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption, UINT uType); """) lib = ffi.dlopen("USER32.DLL") lib.MessageBox(ffi.NULL, "Hello, world!", "Title", 0)
Yeah, that's loads better than 0.5. Presumably ffi.NULL isn't needed and I can use 0? (After all, 0 and NULL are equivalent in C, so that's not a correctness issue). The auto-conversion of strings is a huge improvement.
That's a slightly unfair example, because in this case it happens to work with ctypes without specifying the argtypes and the restype. I would argue that this feature of ctypes is not a good thing: it's mostly the same as saying "you only need to declare argtypes and restype if you get nonsense results or segfaults".
That's a bit unfair. I'd say "you only need to declare argtypes if you're dealing with things more complex than integers, strings and null pointers". Which means you're fine for a huge proportion of the Windows API.
No, if the int is of the wrong size or you pass int instead of float (but you meant float) you get nonsense or segfaults.