Random Access I/O

[data pulverizer via Digitalmars-d-learn]

On Saturday, 26 March 2016 at 00:10:23 UTC, Chris Williams wrote:
> I need to be able to perform random access I/O against a file, 
> creating a new file if it doesn't exist, or opening as-is (no 
> truncation) if it already exists.
>
> None of the access modes for std.stdio.File seem to allow that. 
> Any usage of the "w" mode causes my code to consider the file 
> empty if it pre-exists (though, it doesn't always actually 
> truncate the disk on file?)
>
> If I was coding in C, I would use open() as it gives more 
> options for access:
>
> http://pubs.opengroup.org/onlinepubs/009695399/functions/open.html
>
> However, I don't see this exposed in phobos anywhere?

The Programming in D book chapter on Files 
http://ddili.org/ders/d.en/files.html will help. I think the 
"std.stdio.File struct" section on the same page has what you 
need. Also, take a look at 
http://dlang.org/phobos/std_stdio.html#.File.open.