[Issue 16487] Add function to obtain the available disk space

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16487

--- Comment #4 from b2.temp at gmx.com ---
(In reply to Johan Engelen from comment #3)
> Version that actually compiles on Windows too:
> ```
> // Returns ulong.max when the available disk space could not be determined.
> ulong getAvailableDiskSpace(string path)
> {
>     import std.string: toStringz;
>     version (Windows)
>     {
>         import std.path;
>         import core.sys.windows.winbase;
>         import core.sys.windows.winnt;
>         import std.internal.cstring;
> 
>         ULARGE_INTEGER freeBytesAvailable;
>         path ~= dirSeparator;
>         auto success = GetDiskFreeSpaceExW(path.tempCStringW(),
> &freeBytesAvailable, null, null);
>         return success ? freeBytesAvailable.QuadPart : ulong.max;
>     }
>     else
>     {
>         import core.sys.posix.sys.statvfs;
> 
>         statvfs_t stats;
>         int err = statvfs(path.toStringz(), &stats);
>         return !err ? stats.f_bavail * stats.f_frsize : ulong.max;
>     }
> }
> ```

what I would say if it'd be a PR:

1. change declaration to 

    ulong getAvailableDiskSpace(const(char)[] path) 

because const(char)[] acts as a wildcard and takes all char[] variants.

2. returns -1 on failure. ulong.max: No way !!!

3. linux version: don't need to init the target so

    statvfs_t stats = void;

Otherwise let's get the merge ;)

--