I've created a pull request https://github.com/cffi/cffi/pull/27.

On Tue, Jul 30, 2013 at 11:23 PM, Felix Filozov <ffilozov@gmail.com> wrote:

Having had a closer look at the code, I noticed that the with-foreign-pointer macro allocates in a static area if #+(version>= 8 1).

Perhaps it's better to add additional calls to #+(version>= 8 1) in the %foreign-funcall macro, and the defcfun-helper-forms function, so that if #+(version>= 8 1) the appropriate options are set to allow for GC to run during foreign function execution.

On Tue, Jul 30, 2013 at 5:33 PM, Felix Filozov <ffilozov@gmail.com> wrote:

Hi all,

When defining a foreign function using def-foreign-call, there's an option one could set called :allow-gc. Setting it to :always, allows the garbage collector to run while the foreign function is executing.

At the moment CFFI uses the default value for :allow-gc, which is :never. This prevents GC from running when a foreign function is executing.

Moreover, once GC blocks, other processes can't make progress. In my case, I need GC to run during foreign function execution.

What do you think about extending the defcfun and foreign-call interfaces to allow for native options to be passed? name-and-options could be extended to accept a new argument, :native-args, for example. Then you'd be able to use defcfun as follows:

(defcfun ("strlen" :native-args (:allow-gc :always)) :int

  (str :string))

Another option is to create a global variable that holds native arguments, and def-foreign-call would read this directly.

Thanks,

Felix