[Pyrex] Pyrex and the GIL

[Andrew Bennetts]

On Wed, Sep 07, 2005 at 03:58:26PM +1200, Greg Ewing wrote:
> Simon Burton wrote:
> 
> >And inversely: some syntax to indicate that a particular c function
> >call can release the GIL.
> 
> That's actually where I came from initially on this.
> I was thinking of having a declaration like
> 
>   cdef extern int foo(int blarg) nogil
> 
> where "nogil" means "this function expects the GIL to be
> released when it is called". Whenever it is called in a
> Pyrex function, code would be generated to release the
> GIL, call the function, and then re-acquire the GIL.

I'd call this acquire_gil, or perhaps acquires_gil.

> Then I realised that the *same* declaration could be
> used the other way round, too. If you write
> 
>   cdef void my_callback() nogil
>     ...code here...
> 
> you're saying "the GIL will be released when this
> function is called". So Pyrex will generate code to
> acquire the GIL before executing the function body
> and release it again afterward.

And then I'd call this one releases_gil.

> Is that neat? Or too confusing?

I think it is perhaps a little too confusing.  I think
acquires_gil/releases_gil is clearer and more descriptive, but I haven't
spent a huge amount of effort thinking about it.

-Andrew.