I'd like to use fread and fwrite in place of File.rawRead and File.rawWrite which force the creation of an array where I'd rather specify a buffer location and length. I'd like to do this using a File object but the handle for the C stream is a private member and I can't find any way to access it. Is there a getter or something I missed, or else some way to pry private data like this out of a class?

Answered my own question: Turns out File.getFP() does exactly what I needed

On 10/22/2015 11:20 AM, pineapple wrote:
> I'd like to use fread and fwrite in place of File.rawRead and
> File.rawWrite which force the creation of an array where I'd rather
> specify a buffer location and length.

Would you not create that buffer? :)

If you already have a piece of memory, it is trivial to convert it to a slice in D:

  auto slice = existing_pointer[0 .. number_of_elements];


http://ddili.org/ders/d.en/pointers.html#ix_pointers.slice%20from%20pointer

The operation is not expensive because D slices are nothing but a pointer and length.

Ali

On Thursday, 22 October 2015 at 18:20:07 UTC, pineapple wrote:
> I'd like to use fread and fwrite in place of File.rawRead and File.rawWrite which force the creation of an array where I'd rather specify a buffer location and length.

D's arrays *are* just buffer locations and lengths with a few extra properties, methods and operators.

T* ptrToBuffer = /* ... */;
size_t lengthOfBuffer = /* ... */;
T[] buffer = ptrToBuffer[0 .. lengthOfBuffer];
File f = /* ... */;
T[] filledPartOfBuffer = f.rawRead(buffer);

Note that at no point in the above is a new buffer allocated.

On Thursday, 22 October 2015 at 18:28:50 UTC, Ali Çehreli wrote:
> If you already have a piece of memory, it is trivial to convert it to a slice in D:
>
>   auto slice = existing_pointer[0 .. number_of_elements];
>
>
> http://ddili.org/ders/d.en/pointers.html#ix_pointers.slice%20from%20pointer
>
> The operation is not expensive because D slices are nothing but a pointer and length.
>
> Ali

Cool, I hadn't realized slices worked like that. Still, it was more convenient to use fread and fwrite in this case. I had an pointer where I wanted to be able to read and write one byte at a time and fread/fwrite are familiar and comfortable options to me.