On Friday, September 2, 2011 11:53:43 AM UTC-7, Adam Skutt wrote: > On Sep 2, 2:23 pm, Alain Ketterlin <al...@dpt-info.u-strasbg.fr> > wrote: > > Sorry, you're wrong, at least for POSIX threads: > > > > void pthread_exit(void *value_ptr); > > int pthread_join(pthread_t thread, void **value_ptr); > > > > pthread_exit can pass anything, and that value will be retrieved with > > pthread_join. > > No, it can only pass a void*, which isn't much better than passing an > int. Passing a void* is not equivalent to passing anything, not even > in C. Moreover, specific values are still reserved, like > PTHREAD_CANCELLED. Yes, it was strictly inappropriate for me to say > both return solely integers, but my error doesn't meaningful alter my > description of the situation. The interface provided by the > underlying APIs is not especially usable for arbitrary data transfer.
I'm sorry, but your claim is flat out wrong. It's very common in C programming to use a void* to give a programmer ability to pass arbitrary data through some third-party code. The Python API itself uses void* in this way in several different places. For instance, ake a look at the Capsule API (http://docs.python.org/c-api/capsule.html). You'll notice it uses a void* to let a user pass in opaque data. Another case is when declaring properties in C: it's common to define a single get or set function, and only vary some piece of data for the different properties. The API provides a void* so that the extension writer can pass arbitrary data to the get and set functions. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
