>>>>Cetin and Ed:
>>>>
>>>>With your help now this code is working. But sometimes DoubleToNum function provokes C000005 error.
>>>>
>>>>Indeed I am forgetting something.
>>>>
>>>>Alejandro Fernandez
>>>Alejandro,
>>>Are you sure it's DoubleToNum invoking C000005 ? Might it something else with DLL.
>>>Cetin
>>
>>I found this error tracing the source with SET STEP ON.
>
>That will happen if the address in memory is not valid; either it's non-existant, or you do not have read privileges for the address. Check the value of the pointer - some people's implementation of the DWORDToNum() UDF is subtly flawed, since VFP treats a 4 byte integer as a value between -2147483647 to 2147483647, not 0 to 4294967295.

C000005 error appear sometimes when and UDF is called too. It's not always in DoubleToNum function. Sometimes calling my DLL provokes the same error.

I had thought to check pointer in order to avoid it, but I don`t know exactly what function to use here.

Thanks.

Alejandro.