Python:如何增加ctypes POINTER实例 [英] Python: how to increment a ctypes POINTER instance

问题描述

假设p = ctypes.cast("foo", ctypes.POINTER(ctypes.c_char)).

因此，我们有p.contents.value == "f".

如何直接访问和操纵(例如递增)指针?例如.就像(p + 1).contents.value == "o".

How can I directly access and manipulate (e.g. increment) the pointer? E.g. like (p + 1).contents.value == "o".

推荐答案

您必须使用索引:

>>> p = ctypes.cast("foo", ctypes.POINTER(ctypes.c_char))
>>> p[0]
'f'
>>> p[1]
'o'
>>> p[3]
'\x00'

看看ctypes文档了解有关使用指针的更多信息.

Have a look at ctypes documentation to find out more about using pointers.

更新:看来这不是您所需要的.然后，让我们尝试另一种方法:首先将指针转换为void，将其递增，然后将其转换回LP_c_char:

UPDATE: It seems that it's not what you need. Let's, then, try another approach: first cast the pointer to void, increment it and then cast it back to LP_c_char:

In [93]: p = ctypes.cast("foo", ctypes.POINTER(ctypes.c_char))

In [94]: void_p = ctypes.cast(p, ctypes.c_voidp).value+1

In [95]: p = ctypes.cast(void_p, ctypes.POINTER(ctypes.c_char))

In [96]: p.contents
Out[96]: c_char('o')

也许它并不优雅，但可以.

Maybe it's not elegant but it works.

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