[M3devel] malloc/free from Modula-3?

[Tony Hosking]

Yes, I think you should avoid -pthread.


Antony Hosking | Associate Professor | Computer Science | Purdue University
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On Apr 18, 2011, at 12:10 PM, Mika Nystrom wrote:

> 
> Tony Hosking writes:
>> I suspect the problem is re-entrance to the library. Should you be =
>> disabling user thread switching somewhere?
> 
> I suspect the same.  That's why I asked what the "rules" are
> for calling malloc and free.  I notice that the m3core code has
> Scheduler.DisableSwitching around all calls to malloc but not around calls
> to free.  Why would one be unsafe and the other safe?  It is always free
> that my program hangs up on by the way.  Surrounding all "suspicious" calls
> in my code with Scheduler.DisableSwitching doesn't solve the problem, as
> far as I can tell.
> 
> I am further suspecting that my problem is related to my having linked the
> program with -pthread.  I am also guessing that this is the same reason
> you can't link FreeBSD user threads programs with -pthread: namely that if
> you go reentrantly into the pthread malloc library some code assumes 
> the two invocations are from separate threads and locks up if they are from
> the same thread.  That's my guess anyhow.  But that doesn't explain why
> I've never seen any malloc/free problems on FreeBSD without -pthread.
> (I don't think I have, anyhow.)
> 
>    Mika