Writing very large files 50+ GB

[wmunger]

I need to write to a file that is 50 to 250GB on all three major 
operating systems.

I tried to use the c function pwrite64.  But it is not available 
on the Mac.

I have seen where some have used the iostream in C++ but this 
does not seem to work on the Mac.

Is there any way to write in D very large files.  After all I 
would rather write in D than wrap C or C++ code.

Thank you.