[pypy-dev] cffi dlopen

[Roshan Cherian]

Thanks Armin and Maciej. I now have the code running on a box without gcc
on it and I don't use ffi.dlopen, I now distribute the generated
_ical_cffi_ext.c which was generated using ffi.compile() and use distuitils
to build it to site-packges of pypy. Thanks a lot for this.

I do have a question on memory management, currently I am using lib.
Currently lib provides me with icalcomponent_free which I pass in as the
function to be used in __del__. Should I be using this or should I be using
something specific from the python extension? This is what I see in the
python extension which was created.

static void _cffi_d_icalcomponent_free(icalcomponent * x0)
{
  icalcomponent_free(x0);
}
#ifndef PYPY_VERSION
static PyObject *
_cffi_f_icalcomponent_free(PyObject *self, PyObject *arg0)
{
  icalcomponent * x0;
  Py_ssize_t datasize;

  datasize = _cffi_prepare_pointer_call_argument(
      _cffi_type(1), arg0, (char **)&x0);
  if (datasize != 0) {
    if (datasize < 0)
      return NULL;
    x0 = (icalcomponent *)alloca((size_t)datasize);
    memset((void *)x0, 0, (size_t)datasize);
    if (_cffi_convert_array_from_object((char *)x0, _cffi_type(1), arg0) <
0)
      return NULL;
  }

  Py_BEGIN_ALLOW_THREADS
  _cffi_restore_errno();
  { icalcomponent_free(x0); }
  _cffi_save_errno();
  Py_END_ALLOW_THREADS

  (void)self; /* unused */
  Py_INCREF(Py_None);
  return Py_None;
}
#else
#  define _cffi_f_icalcomponent_free _cffi_d_icalcomponent_free
#endif

Thanks for the help,
-Roshan

On Fri, Sep 18, 2015 at 3:49 AM, Armin Rigo <arigo at tunes.org> wrote:

> Hi Roshan,
>
> On Fri, Sep 18, 2015 at 10:02 AM, Roshan Cherian <cherian.rosh at gmail.com>
> wrote:
> > _icaltimezonechange is opaque as its in src/libical/icaltimezone.c a c
> file
> > and not in in ical.h. However this struct is required for my purpose.
>
> All structs must be declared in C before you import them into Python.
> In this case, the "cheat" to access this structure is the same as if
> you wrote C code: you need to give the real C compiler a declaration
> of this struct.  Then you can import it as you did.  (So you need to
> write this struct twice.)
>
> ffi.set_source("_ical_cffi_ext",
>     """ // passed to the real C compiler
>         #include <libical/ical.h>
>
>         struct _icaltimezonechange {
>             int          utc_offset;
>             int          prev_utc_offset;
>             int          year;          /**< Actual year, e.g. 2001. */
>             int          month;         /**< 1 (Jan) to 12 (Dec). */
>             int          day;
>             int          hour;
>             int          minute;
>             int          second;
>             int          is_daylight;
>         };
>     """,
>         include_dirs=['./include'],    # where ical.h is
>         libraries=['ical'],
>         library_dirs=['./lib'],)   # or a list of libraries to link with
>
>
> A bientôt,
>
> Armin.
>
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