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Get free disk space C++

Posted on 1998-02-05
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Last Modified: 2008-02-01
I have a function that calculates the available space on a disk drive.  It works fine for NT and for WIN 95 older version.  It does not work for newer release of WIN 95 (service pack 2+).  The problem is that I can't
get the adress of the 'GetDiskFreeSpaceEx' in KERNEL32.DLL.

This is the code:

/********************************************************************
procedure:            GetDriveFreeSpace
input:                  CString directory - Source directory
return:                  double
description:      Return the amount of free space on the drive of the
                        given directory (in bytes)
********************************************************************/

typedef BOOL (*FREE_SPACE_FUNCTION_DEFINITION) (LPCTSTR, PULARGE_INTEGER, PULARGE_INTEGER, PULARGE_INTEGER);

double GetFreeDriveSpace(CString directory)
{
      OSVERSIONINFO version_information;
      CString drive;
      short position;
      
      ASSERT(directory.GetLength() >= 0);

      // Get drive name
      position = (short) directory.Find(_TEXT(":"));

      if (position >= 0) {
            if (position == 0) {
                  // The colon is the first character
                  ASSERT(FALSE);
                  return (0);
            }
            drive = directory.Left(position + 1);
      }
      else {
            // Assume entire directory string is name
            drive = directory + _TEXT(":");
      }

      // Initialize structure
      version_information.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);

      // Get version of Windows
      if (GetVersionEx(&version_information) == FALSE) {
            // Couldn't get version number
            ASSERT(FALSE);
            return (0);
      }

      if (version_information.dwPlatformId == VER_PLATFORM_WIN32_NT) {
            /// I deleted this part since it works for NT
      }
      else if (version_information.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS) {
            // Windows 95 is running

            // Check if service pack 2+ has been installed
            if ((version_information.dwBuildNumber & 0xffff) <= 1000) {
                  // Service pack not installed
                  /// I deleted this part since it works for WIN 95 prior to service pack 2+
            }
            else {
                  // Service pack installed

                  // Use function from DLL
                  HINSTANCE instance;
                  FREE_SPACE_FUNCTION_DEFINITION procedure_address;
                  ULARGE_INTEGER total_free_space_for_user;
                  ULARGE_INTEGER total_free_space;
                  ULARGE_INTEGER total_space;

                  // Load DLL into memory
                  instance = LoadLibrary("KERNEL32.DLL");

                  // Check load
                  if (instance == NULL) {
                        ASSERT(FALSE);
                        return (0);
                  }

                  // Get function address
                  // THE NEXT LINE DOES NOT WORK
                  // PROBLEM: procedure_adress is allways NULL
                  procedure_address = (FREE_SPACE_FUNCTION_DEFINITION) GetProcAddress(instance,
                        "GetDiskFreeSpaceEx");

                  if (procedure_address == NULL) {
                        ASSERT(FALSE);
                        return (0);
                  }

                  // Get free disk space
                  if (procedure_address(drive, &total_free_space_for_user, &total_space,
                        &total_free_space) == FALSE) {
                        return (0);
                  }
                  else {
                        return (((double) FOUR_GIGABYTES * (double) total_free_space_for_user.HighPart) +
                              (double) total_free_space_for_user.LowPart);
                  }
            }
      }
      else {
            // Windows 3.1 is running
            ASSERT(FALSE);
            return (0);
      }
}
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Question by:fhoule
  • 2
3 Comments
 
LVL 7

Accepted Solution

by:
galkin earned 200 total points
ID: 1180874
This function has two version. One is ANSI GetDriveFreeSpaceExA and another one is UNICODE GetDriveFreeSpaceExW. So you need either to define GetDriveFreeSpaceEx depending on copiling(UNICODe or ANSI) and use #define precompiler statement or to explicity get address of appropriate version of this function.
0
 

Author Comment

by:fhoule
ID: 1180875
Galkin, Thanks for the EXTRA quick response !
0
 

Author Comment

by:fhoule
ID: 1180876
I was a bit quick to provide the points....

The GetProcAddress still return NULL

I got the error code with GetLastError and got error 126
"The specified module could not be found. "

galkin, do you have an idea ???
Thanks in advance.
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