ffi: support programmable abort return value.

* ffi.c (stuct txr_ffi_closure): New member, abort_retval.
(ffi_closure_mark_op): Mark the new member.
(ffi_closure_dispatch_safe): Implement the abort_retval.
If it is not nil, use put to place the value into the
return buffer.  There is a risk that this could also throw
an exception, which is no longer protected: programer's
problem.
(ffi_make_closure): New abort_ret_in argument, which is
defaulted and stored.
(ffi_init): Update registration of ffi-make-closure to
reflect new argument.

* ffi.h (ffi_make_closure): Declaration updated.

* share/txr/stdlib/ffi.tl (sys:deffi-cb-expander):
Add abort-retval parameter; insert into ffi-make-closure
call.
(deffi-cb): Take optional abort-retval expression;
pass it down to the expander function.
(deffi-cb-unsafe): Pass nil as abort-retval down to expander.

* txr.1: Documented.

0 files changed, 0 insertions, 0 deletions