UFFI - Could not coerce arguments

I would like to pass a pointer to an array of pointers to a FFI call and I have problems ...

​I have this method:

runOutputs: aTF_OutputArray size: anInteger
    | status outvalues |
    status := TF_Status create.
    outvalues := FFIExternalArray externalNewType: 'TF_Tensor*' size: anInteger.
    self library
        runSession: self
        options: FFIExternalObject null
        inputs: FFIExternalObject null
        values: FFIExternalObject null

        count: 0
        outputs: aTF_OutputArray getHandle
        values: outvalues getHandle
        count: anInteger
        targets: FFIExternalObject null
        count: 0
        metadata: FFIExternalObject null
        status: status.
    status check.
    ^ outvalues

​the FFI call is like that :

runSession: aTF_Session
    options: opsTF_Buffer
    inputs: inTF_OutputArray values: inTF_TensorArray count: inCount
    outputs: outTF_OutputArray values: outTF_TensorArrayPtr count: outCount
    targets: aTF_OperationArray count: targetCount
    metadata: metaTF_Buffer
    status: aTF_Status
   
    "F_CAPI_EXPORT extern void TF_SessionRun(
    TF_Session* session,
    // RunOptions
    const TF_Buffer* run_options,
    // Input tensors
    const TF_Output* inputs, TF_Tensor* const* input_values, int ninputs,
    // Output tensors
    const TF_Output* outputs, TF_Tensor** output_values, int noutputs,
    // Target operations
    const TF_Operation* const* target_opers, int ntargets,
    // RunMetadata
    TF_Buffer* run_metadata,
    // Output status
     TF_Status*);"
       
        ^ self
        ffiCall: #(void TF_SessionRun #(TF_Session * aTF_Session, TF_Buffer * opsTF_Buffer, TF_Output * inTF_OutputArray, TF_Tensor * inTF_TensorArray, int inCount, TF_Output * outTF_OutputArray, TF_Tensor * outTF_TensorArrayPtr, int outCount, TF_Operation * aTF_OperationArray, int targetCount, TF_Buffer * metaTF_Buffer, TF_Status * aTF_Status))
        module: TensorFlowCAPI

TF_Tensor is an opaque object.

I have an error: "Could not coerce arguments".

I guess this is related to the way I pass arguments to the FFI function ?

--

Serge Stinckwich
UMI UMMISCO 209 (SU/IRD/UY1)

"Programs must be written for people to read, and only incidentally for machines to execute."

http://www.doesnotunderstand.org/

hi,

it all depends on how you are declaring your types.

here, for example you are passing 

aTF_OutputArray getHandle

that’s a “void*” value (an ExternalAddress or ExternalData object), and in declaration you have (if I read correctly):

TF_Output * 

so, first question is: if TF_Output != void, then you have a coercing problem :).

you can fix that just changing the notation to receive a void * (in C is all the same, but not in pharo :)) 

note that this can be happening in a lot of places, since your function has a lot of arguments, I just put an example of what can be wrong.