How can I determine the space/size of my drive programatically? Both in LInux and on Windows

That is : Ho开发者_如何学Gow can I check the drive size which is not formatted... Don't consider the formatted drives...just unformatted drive.

Under Linux, if you want the size of the entire drive, read /sys/block/sda/size.

To find the size of a partition, read /sys/block/sda/sda1/size.

Replace sda, sda1 with names of your devices/partitions.

Or, if you can open the raw device file, you can use the BLKGETSIZE ioctl.

Programmatically in Linux:

#include <fcntl.h>
#include <linux/fs.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv)
{
  int fd;
  unsigned long long numblocks=0;

  fd = open(argv[1], O_RDONLY);
  ioctl(fd, BLKGETSIZE64, &numblocks);
  close(fd);
  printf("Number of bytes: %llu, this makes %.3f GB\n",
     numblocks, 
     (double)numblocks / (1024 * 1024 * 1024));
}

This is basically the code from http://www.linuxproblem.org/art_20.html, adapted to use BLKGETSIZE64, with various warnings fixed.

$ gcc -o getsize getsize.c
$ sudo ./getsize /dev/sda
Number of bytes: 53687091200, this makes 50.000 GB

for windows.. you can use DeviceIoControl().

#include <windows.h>
#include <winioctl.h>
#include <stdio.h>

BOOL GetDriveGeometry(DISK_GEOMETRY *pdg)
{
  HANDLE hDevice;               // handle to the drive to be examined 
  BOOL bResult;                 // results flag
  DWORD junk;                   // discard results

  hDevice = CreateFile(TEXT("\\\\.\\PhysicalDrive0"),  // drive 
                    0,                // no access to the drive
                    FILE_SHARE_READ | // share mode
                    FILE_SHARE_WRITE, 
                    NULL,             // default security attributes
                    OPEN_EXISTING,    // disposition
                    0,                // file attributes
                    NULL);            // do not copy file attributes

  if (hDevice == INVALID_HANDLE_VALUE) // cannot open the drive
  {
    return (FALSE);
  }

  bResult = DeviceIoControl(hDevice,  // device to be queried
      IOCTL_DISK_GET_DRIVE_GEOMETRY,  // operation to perform
                             NULL, 0, // no input buffer
                            pdg, sizeof(*pdg),     // output buffer
                            &junk,                 // # bytes returned
                            (LPOVERLAPPED) NULL);  // synchronous I/O

  CloseHandle(hDevice);

  return (bResult);
}

int main(int argc, char *argv[])
{
  DISK_GEOMETRY pdg;            // disk drive geometry structure
  BOOL bResult;                 // generic results flag
  ULONGLONG DiskSize;           // size of the drive, in bytes

  bResult = GetDriveGeometry (&pdg);

  if (bResult) 
  {
    printf("Cylinders = %I64d\n", pdg.Cylinders);
    printf("Tracks/cylinder = %ld\n", (ULONG) pdg.TracksPerCylinder);
    printf("Sectors/track = %ld\n", (ULONG) pdg.SectorsPerTrack);
    printf("Bytes/sector = %ld\n", (ULONG) pdg.BytesPerSector);

    DiskSize = pdg.Cylinders.QuadPart * (ULONG)pdg.TracksPerCylinder *
      (ULONG)pdg.SectorsPerTrack * (ULONG)pdg.BytesPerSector;
    printf("Disk size = %I64d (Bytes) = %I64d (Gb)\n", DiskSize,
           DiskSize / (1024 * 1024 * 1024));
  } 
  else 
  {
    printf ("GetDriveGeometry failed. Error %ld.\n", GetLastError ());
  }

  return ((int)bResult);
}