>>You can use 3 VFP strings initialized with repl(chr(0), 8) for the 3 ULARGE_INTEGER parameters. Be aware that
>>GetDiskFreeSpaceEx() does not return an error (everything works just like there's nothing wrong if called on
>>Win95 previous OSR2).
>>
>>I don't understand where is VFP using floating point numbers for this function call.
>>
>
>I believe that integers at ~2^32 stop being returned as integers and start being doubles. I haven't checked he crossover point in detail

VFP doesn't know that you allocated 8 bytes instead of 4. And the DLL function has no reason to work with doubles. So, nobody converts anything.

Vlad