[squeak-dev] FFI problem: "could not coerce arguments"

On Mon, May 26, 2008 at 10:36 AM, Bert Freudenberg <[hidden email]> wrote:

On 26.05.2008, at 15:21, Mariano Martinez Peck wrote:

"could not coerce arguments"

int odbx_set_option(
   odbx_t* handle,
   unsigned int option,
   void* value )

apiSetOption: handle option: anOption value: aValue
   "int odbx_unbind(odbx_t*)"
   <cdecl: long 'odbx_set_option' (ulong ulong void*) module: 'opendbx' >
   ^self externalCallFailed

err := OpenDBX apiSetOption: self option:32  value:1.

The first argument appears to be a pointer to a handle object. You probably should not declare that as ulong if you then pass "self" (which I assume is a ExternalStructure subclass). But that depends on how you acquire the handle, and how you represent it in the image.

Yes you are right, sorry. It was not self, but a attribute called handle. My mistake.
 

The argument to void* should be a ByteArray or WordArray, methinks, I'd try "WordArray with: 1" if you want to pass a pointer to the Integer 1.

- Bert -

Sounds interesting. I will test it and then I tell you.

Thanks,

Mariano

 

Am 18.08.2008 um 21:29 schrieb Bert Freudenberg:

Am 18.08.2008 um 20:44 schrieb Mariano Martinez Peck:

On Mon, May 26, 2008 at 10:44 AM, Mariano Martinez Peck <[hidden email]> wrote:


On Mon, May 26, 2008 at 10:36 AM, Bert Freudenberg <[hidden email]> wrote:

On 26.05.2008, at 15:21, Mariano Martinez Peck wrote:

"could not coerce arguments"

int odbx_set_option(
 odbx_t* handle,
 unsigned int option,
 void* value )
apiSetOption: handle option: anOption value: aValue
 "int odbx_unbind(odbx_t*)"
 <cdecl: long 'odbx_set_option' (ulong ulong void*) module: 'opendbx' >
 ^self externalCallFailed

err := OpenDBX apiSetOption: self option:32  value:1.


The first argument appears to be a pointer to a handle object. You probably should not declare that as ulong if you then pass "self" (which I assume is a ExternalStructure subclass). But that depends on how you acquire the handle, and how you represent it in the image.

Yes you are right, sorry. It was not self, but a attribute called handle. My mistake.


The argument to void* should be a ByteArray or WordArray, methinks, I'd try "WordArray with: 1" if you want to pass a pointer to the Integer 1.

- Bert -

Sounds interesting. I will test it and then I tell you.



Bert: I test this using WordArray and I work perfect in all the cases the value was a number. But the type in the function definition is void*. So, now, I need to send not only a 1 or 0, but a String. In this case, I cannot do WordArray with: 'aStringValue'  neither ByteArray with: 'aStringValue' . What can I do in this case? Do you have any idea?

I mean, I need to use the same parametrer void*, sending it a number or a string.

Declare the method again like

apiSetOption: handle option: anOption string: aString
 <cdecl: long 'odbx_set_option' (ulong ulong char*) module: 'opendbx' >
 ^self externalCallFailed

and use that by simply passing a String (don't even bother to convert to ByteArray [but watch out for the terminating 0]).

- Bert -

... that is, unless this works with the original method (I'm not sure):

self apiSetOption: handle option: bla value: 'aStringValue' asByteArray.


- Bert -

Am 19.08.2008 um 17:06 schrieb Mariano Martinez Peck:

Yeah!  Bert:

 It works perfectly if I use char* and

self apiSetOption: handle option: bla value: 'aStringValue'

Great. In that case I'd simply keep those two methods apiSetOption:option:value: and apiSetOption:option:string:.

- Bert -