#pragma warning( disable:4001 ) // Disable single line comment warning
///////////////////////////////////////////////////////////////////////////////////////////////////
//
// FILE:    FREEDISK.C  (compiled using Visual C++)
//          (c) 1996 Guillaume Dargaud
//
// PURPOSE: This DLL provides a way for a LabWindows/CVI program to check for available disk size
//          This is meant to be used on Windows 3.1 with MS C ver 1.5 and CVI 32 bits
//
// NOTE:    All exported functions that reference variables in the dll or call functions
//          that reference variables in the dll should probably be declared with __loadds
//          and __far to load the dll's data segment on entry since there is no pagination
//          in CVI. They should also be declared as extern and __export since they are
//          part of a DLL. And finally they should be __cdecl against compilation in C++.
//
// CONTROL MACROS: _LOGFILE: writes information in the log file INTERRUPT.C
//                 _DEBUG: compilation done in debugger mode. Controls expansion of
//                          misc macros such as TRACE, ASSERT...
//
// PROJECT FILES: FREEDISK.C, FREEDISK.DEF
//
// COMPILATION: I recommend the following parameters in DEBUG mode (used for simulation):
//              Compiler: /nologo /G2 /FPi87 /W4 /Zi /ALw /Od /D "_DEBUG" 
//                        /D "_LOGFILE" /FR /GD /Fd"INTERRUPT.PDB"
//              Linker: /NOLOGO /LIB:"oldnames" /LIB:"libw" /LIB:"ldllcew" 
//                      /NOD /NOE /PACKC:61440 /ALIGN:16 /CO /MAP:FULL
//              Resources: _DEBUG
//
//              I recommend the following parameters in RELEASE mode (used for real time acquisition):
//              Compiler: /nologo /Gs /G3 /FPi87 /W3 /ALw /O1 
//                        /D "NDEBUG" /D "NLOGFILE" /FR /GD
//              Linker: /NOLOGO /LIB:"oldnames" /LIB:"libw" /LIB:"ldllcew" 
//                      /NOD /NOE /PACKC:61440 /ALIGN:16 /ONERROR:NOEXE
//              Resources: NDEBUG
//
//              You can then recompile everything for the simulation mode by just selecting
//              the MSVC menu [Options][Project] and the Build Mode [Debug].
//              In the same way, use the Build Mode [Release] for creating a real time DLL
///////////////////////////////////////////////////////////////////////////////////////////////////

#include <dos.h>
#include "DiskFree.h"

/////////////////////////////////////////////////////////////////////////////
// FUNCTION: AvailableDiskSize()
// PURPOSE:  Return available space on disk in bytes
// IN: DiskNum: 1 for A:  2 for B:...
/////////////////////////////////////////////////////////////////////////////
unsigned long PREFIX AvailableDiskSize( unsigned char DiskNum )
{
   union _REGS inregs, outregs;
   inregs.h.ah = 0x36;           // Get disk free space
   inregs.h.dl = DiskNum;  
   _intdos( &amp;inregs, &amp;outregs );
   if (outregs.x.ax==0xFFFF) return 0;
   return (long)outregs.x.ax*outregs.x.bx*outregs.x.cx;
}