Re: [Ctypes-devel] Crash using callback

[Thomas H. <th...@py...>]

Peter Hansen schrieb:
> Victor Stinner wrote:
>> Question: would it be possible to change object lifetime, tell that the 
>> function keep a referrence of the object, or something like that? Or should I 
>> keep a copy of "mycallback = callback_t(mine)" somewhere?
> 
> I'm pretty sure you must keep a reference in Python, or it will be (via 
> reference counting) freed up immediately.  I'm also (slightly less, but 
> still fairly) sure that the documentation on callbacks points something 
> like this out... maybe double-check there again?
> 
Peter is completely right.  You need to keep the callback object alive
*in Python* until it is no longer used by any C code.
If ctypes would keep it alive forever automatically, we would have a memory
leak.

Thomas