Is Python's ctypes.c_long 64 bit on 64 bit systems?

Question

In C, long is 64 bit on a 64 bit system. Is this reflected in Python's ctypes module?

Answer 1

The size of long depends on the memory model. On Windows (LLP64) it is 32-bit, on UNIX (LP64) it is 64-bit.

If you need a 64-bit integer, use c_int64.

If you need a pointer-sized integer, use c_void_p (“The value is represented as integer”).

Answer 2

Actually no.

On a Windows 64-bit system, long is 32 bits.

Python 3.1.2 (r312:79149, Mar 20 2010, 22:55:39) [MSC v.1500 64 bit (AMD64)] on win32
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>>> import ctypes
>>> ctypes.c_long(2**31)
c_long(-2147483648)
>>> ctypes.c_long(2**31+1)
c_long(-2147483647)
>>> ctypes.c_long(2**31-1)
c_long(2147483647)
>>>

See What is the bit size of long on 64-bit Windows?