Re: FFI extension / NULL-Checks
| From: | Christoph M. Becker | Date: | Mon, 09 Sep 2019 12:15:21 +0000 |
| Subject: | Re: FFI extension / NULL-Checks | ||
| References: | 1 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-106918@lists.php.net to get a copy of this message | ||
On 09.09.2019 at 08:03, Philip Hofstetter wrote:
> (I'm writing to the internals list because I don't think that at this
> point, FFI usage is wide-spread enough to get an opinion on other venues)
>
> maybe I'm just stupid, but I think there has been a slight oversight in the
> API design for the FFI interface.
>
> My problem is with functions that return a pointer to a struct as an out
> parameter.
>
> So in C, it would look like this:
>
> Error* err;
> func(&err);
>
> if (err != NULL){
> do_error_handling();
> }
>
> If I translate this to PHP FFI, I would do
>
> $err = $ffi->new("Error*");
> $ffi->func(FFI::addr($err));
>
> if I
var_dump $err, I do see a public {0} property be set to
> NULL or to
> actual error data.
>
> My issue is though: How do I check whether err* as been assgined to?
You could check FFI::addr($err)[0]:
$err = $ffi->new("Error*");
$perr = FFI::addr($err);
$ffi->func($perr);
var_dump(is_null($perr[0]));
FFI::free($perr);
Not sure if it's supposed to require this indirection, though.
--
Christoph M. Becker