[pypy-dev] How to convert python string to C char*?

[Armin Rigo]

Hi Yicong,

On 14 May 2015 at 11:33, Yicong Huang <hengha.mao at gmail.com> wrote:
> To my understanding, "ALL_RESULTS" is used to prevent pypy GC the pointing
> buffer.
> And thus, it is the C callback function's responsibility to free the buffer.
> Am I right?

No.  In my example I just keep storing ffi.new("char[]") objects in
the list, so this list grows forever and leaks.

You really need to see the documentation of the C code for which you
are making a callback.  Maybe it says that the callback needs to
return a string obtained by ``malloc()``, and it will be ``free()``-ed
for you.  In that case you need to call ``lib.malloc()`` from the
library obtained by cffi, after adding "char *malloc(size_t);" to the
cdef().

But I can't guess if I'm correct; it depends on the C code.


A bientôt,

Armin.