On Wed, Sep 17, 2008 at 2:26 AM, Andreas Raab <andreas.raab at gmx.de> wrote:

> Mariano Martinez Peck wrote:
>
>> Igor: I tried what you said but I get the same error. Here is more
>> information:
>>
>> The C function is like this:
>>  int *odbx_result*(
>>    odbx_t* /*handle*/,
>>    odbx_result_t** /*result*/,
>>
>>    struct timeval* /*timeout*/,
>>    unsigned long /*chunk*/ )
>>
>>
>> My method with FFI is this:
>>
>> apiQueryResult: connectionHandle handle: handle timeout: timeout chunk:
>> chunk
>>    <cdecl: long 'odbx_result' (ulong ulong* DBXTimeSpec ulong) module:
>> 'opendbx'>
>>    ^self externalCallFailed
>>
>
> The reason it doesn't work is that the FFI spec doesn't match the C
> function declaration. Both the first and third argument are declared
> pointers in C, and not declared pointers in the FFI. This is particularly
> problematic with the struct timeval since the FFI now expects you to pass
> the struct timeval by value (since you haven't declared it as being a
> pointer) and will not accept nil as argument (since it would have to
> dereference the pointer and consequently crash). Try the following
> declaration instead:
>
> <cdecl: long 'odbx_result' (ulong* ulong* DBXTimeSpec* ulong) module:
> 'opendbx'>
>
> This will accept nil as the parameter for the timeout value.
>


Andreas: You were right. It was that. I changed to DBXTimeSpec* and now I
can send nil.

Many thanks,

mariano



>
> Cheers,
>  - Andreas
>
>
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