CODEWITHSUNDEEP
c++winapicmd
Enes
Enes

Reputation: 283

How to detect letter of USB flash drive

Letter of USB flash drive is changeable and I don't know how can I detect this or if there are more than one flash drive by using C++ or with a console line command(maybe a shortcut is exists like %APPDATA%).

How can I do it?

Upvotes: 0

Views: 2092

Answers (1)

funbringer
funbringer

Reputation: 96

For this case you could use the GetDriveType function:

UINT WINAPI GetDriveType(
  _In_opt_ LPCTSTR lpRootPathName
);

Determines whether a disk drive is a removable, fixed, CD-ROM, RAM disk, or network drive.

This will suffice if the drive type makes no difference to you. If you are interested in listing only USB flash drives, consider checking the SetupDiGetDeviceRegistryProperty function:

BOOL SetupDiGetDeviceRegistryProperty(
  _In_      HDEVINFO         DeviceInfoSet,
  _In_      PSP_DEVINFO_DATA DeviceInfoData,
  _In_      DWORD            Property,
  _Out_opt_ PDWORD           PropertyRegDataType,
  _Out_opt_ PBYTE            PropertyBuffer,
  _In_      DWORD            PropertyBufferSize,
  _Out_opt_ PDWORD           RequiredSize
);

The SetupDiGetDeviceRegistryProperty function retrieves a specified Plug and Play device property.

Here's an example:

#include "stdafx.h"
#include <setupapi.h>
#include <devguid.h>
#include <cfgmgr32.h>

...

HDEVINFO hdevinfo = SetupDiGetClassDevs(&GUID_DEVCLASS_USB,
                                        NULL, NULL, DIGCF_PRESENT);

if (hdevinfo == INVALID_HANDLE_VALUE)
  return -1;

DWORD MemberIndex = 0;
SP_DEVINFO_DATA sp_devinfo_data;

ZeroMemory(&sp_devinfo_data, sizeof(sp_devinfo_data));
sp_devinfo_data.cbSize = sizeof(sp_devinfo_data);

while (SetupDiEnumDeviceInfo(hdevinfo, MemberIndex, &sp_devinfo_data))
{
  DWORD PropertyRegDataType;
  DWORD RequiredSize;
  DWORD PropertyBuffer;

  if (SetupDiGetDeviceRegistryProperty(hdevinfo,
                                       &sp_devinfo_data,
                                       SPDRP_CAPABILITIES,
                                       &PropertyRegDataType,
                                       (PBYTE) &PropertyBuffer,
                                       sizeof(PropertyBuffer),
                                       &RequiredSize))
  {
    if (PropertyBuffer & CM_DEVCAP_REMOVABLE)
    {
      // Do something, copy your files etc
    }
  }     
  MemberIndex++;
}

SetupDiDestroyDeviceInfoList(hdevinfo);

Upvotes: 2

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