Re: [Pythonmidi-devel] Deallocating resources using destructors

[Tony C. <to...@tc...>]

try registering your cleanup function with atexit.
This is supposed to be called when sys.exit is called.
Would you See if this works for you?


At 10:31 AM 11/04/04, you wrote:

>On Oct 29, 2004, at 3:59 AM, Lennart Regebro wrote:
>
>>A big problem popped up yesterday:
>>
>>It turns out that a Python objects __del__ does not necessarily get 
>>called when a program exits. I knew this once, but I had forgotten it.
>>
>>This means the ports does not get closed unless you specifically call 
>>close on the objects. This is major bug for a Python program, where the 
>>garbage collection is supposed to make sure you never have to deallocate 
>>resources. It's also makes my computer crash. Not immediatly mind you, 
>>but say, 30 minutes later, or so. XP just silently goes *poof* and 
>>reboots. NOT fun! (It's probably crappy MIDI drivers that cause this).
>>
>>The solution to this is supposed to be to write the whole python object 
>>in C, instead of just wrapping the c methods in a python object. C 
>>objects do get properly deallocated when a program exits, I'm told. Now, 
>>that means that the C code suddenly gets MUCH more complex (and it wasn't 
>>exactly trivial before either) so I'm gonna look at doing this in Pyrex.
>
>I'm not sure where you got the idea that C objects get deallocated when a 
>program exits. It's true that stack-local variables of simple type such as 
>integers or chars will be automatically released because the entire stack 
>is released when the program exits, but this has nothing to do with 
>externally allocated resources such as memory allocated with malloc, 
>opened file handles, or opened midi ports. In fact, it is absolutely 
>impossible to arrange for some code to be invoked upon the unexpected 
>termination of your c program.
>
>In general, relying on destructors to free externally allocated resources 
>is a bad, bad idea. Rather than attempting to rewrite your program in C, I 
>would suggest you just rewrite the python portion to explicitly free 
>resources in case of unexpected error (using a try: finally: block, for 
>example.)
>
>dp
>
>
>
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