Calling a cpp function from d

[Daniel Kozák via Digitalmars-d-learn]

On Tue, 16 Jun 2015 12:26:45 +0000
C2D via Digitalmars-d-learn <digitalmars-d-learn at puremagic.com> wrote:

> Hi,
> I encountered the following error:
> 
> Error: function files.SHGetFolderPath (void* hwndOwner, int 
> nFolder, void* hToken, uint dwFlags, char* pszPath) is not 
> callable using argument types (typeof(null), int, typeof(null), 
> int, immutable(char)*)
> 
> When I'm try to run this code:
> ...
> {
> import std.utf : toUTF8;
> static string cache;
> 
> wchar[MAX_PATH + 2] buf;
> 
> BOOL result = SHGetFolderPath(null, 0x23, null, 0, cache.ptr);
> 
> return cache;
> }
> ...
> extern(Windows) HRESULT SHGetFolderPath(HWND hwndOwner, int 
> nFolder, HANDLE hToken, DWORD dwFlags, LPTSTR pszPath);
> 
> I tried everything I know about D and CPP. What can be the 
> solution?

Something like this should work

import std.string : fromStringz;
import std.traits : PointerTarget;

auto buf = new PointerTarget!LPTSTR[MAX_PATH + 2];
auto result = SHGetFolderPath(null, 0x23, null, 0, buf.ptr);
return fromStringz(buf);