WinAPI calls to access USB storage which has no drive letter?

Question

I've noticed, that some USB storage devices don't register in Windows as regular drives, in that they don't even get assigned a drive letter. Therefore, I can't apparently access them using the standard file operations C API.

What are the WinAPI calls I can use to do some normal file operations on those strange devices - so:

• find/enumerate those devices at all,
• browse the file/directory tree on the device and get some file stats (size, modification date, etc.),
• read/write contents of the files,
• create/delete files/directories?

Also, what are the general keywords by which those kinds devices/protocol are known/called?

Answer 1

If you're talking about mobile devices that appears like mounted volumes but without any mounted points, well they are called Windows Portable Devices and they are not mounted volumes.

Windows doesn't access the file system directly, it only communicates with them through the Media Transfer Protocol (MTP) or Picture Transfert Protocol (PTP) and creates a shell namespace extension to present a virtual folder to the user.

If you want to communicate with these kind of devices, then you most probably want to use the WPD API.