A mutual exclusion device is necessary.
OW_get, OW_put, and OW_finish all lock the common mutex.
If OW_get and OW_put /really can/ be used simultaneously, then a
condition is required:
in OW_get and OW_put:
LOCK(mutex);
level++;
UNLOCK(mutex);
{ real code }
LOCK(mutex);
level--;
SIGNAL(cond);
UNLOCK(mutex);
and in OW_finish:
LOCK(mutex);
while (level > 0) COND(cond,mutex);
{ destroy interface safely now }
UNLOCK(mutex);
in pthreads this is:
pthread_cond_t cond;
pthread_mutex_t mutex;
#define COND(q,p) pthread_cond_wait(&q,&p)
#define SIGNAL(q) pthread_cond_signal(&q)
#define LOCK(q) pthread_mutex_lock(&q)
#define UNLOCK(q) pthread_mutex_unlock(&q)
NOTE: this is NOT the same mutex as you're using for acessing indev
(capi_mutex) - but a different one JUST for this cond variable.
BY THE WAY, shouldn't these things be static? Is there really a reason
user programs should have access to it?
On Sun, 2005-10-16 at 22:57 -0400, Paul Alfille wrote:
> Added the same protection for the SWIG prototype (owperl, owpython, owphp).
>
> It occurs to me that it is possible that a "OW_finish" could be called while
> an OW_get or OW_put is in progress -- could be messy since the adapters would
> be disappearing while being used. I'll have to get out the old textbook to
> figure the proper flag for this one -- a semaphore?
>
> Paul
>
> On Sunday 16 October 2005 01:33 am, Paul Alfille wrote:
> > Ok uploaded some OWCAPI changes.
> >
> > 1. I've put in your char** mode. I'm really starting to warm up to it.
> >
> > 2. Protection against multiple "init"s, no "init"s, simultaneous "init"s...
> >
> > Paul
>
>
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