Hello,
(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` $err, I do see a public {0} property be set to NULL or to
actual error data.
My issue is though: How do I check whether err* as been assgined to?
isset($err)
$err[0] != null
-> is always true, regardless of whether func as assigned an error or not
isset($err->{0})
isset($err[0])
-> Cannot use object of type FFI\CData as array
$err->{0} != NULL;
-> FFI\Exception: NULL pointer dereference
$err[0];
-> segfault
I'm sure I must be doing something wrong, but I don't know what. Also, the
documentation could do with an example on how to achieve the desired result
and, TBH, I think some of the various attempts produce a somewhat
unexpected output.
Any comments?
Philip
var_dump(isset($r->{0}));
-> Error: Cannot use object of type FFI\CData as array
$a = '{0}';
var_dump(isset($r->$a));
-> Error: Cannot use object of type FFI\CData as array
var_dump(isset($r[0]));
var_dump($r[0]);
