中国DOS联盟

DOS6.2 + BC3.1

实际项目中是图形界面，drive=0,1 时（A：，B：），_chdrivee有效，
但_dos_getdiskfree出错，应该是在执行21号中断是提示出错信息(General failure reaing drive A)，破坏图形环境。
另外用 DUSE49 加载驱动参数为 drivers=3,则后两个盘符也会提示出错信息（Invalid unit reading drive F）。

Windows XP 下执行是光驱和虚拟光驱报错。

有什么办法不出现提示信息？自己知道这个驱动器不能用就行了。

代码如下：

C/C++ code

// crt_getdrive.c

// compile with: /c

// Illustrates drive functions including:

//    _getdrive       _chdrive        _getdcwd

//



#include <dos.h>

#include <stdio.h>

#include <direct.h>

#include <stdlib.h>

#include <ctype.h>

int main( void )

{

   int ch, drive, curdrive;

   long LM;

   static char path;

   struct diskfree_t diskspace;



   curdrive = _getdrive();   // Save current drive. 

   for( drive = 1; drive <= 26; drive++ )  // If we can switch to the drive, it exists.

   {

      if( !_chdrive( drive ) )

      {

         printf( "%c:", drive + 'A' - 1 );



         if( _getdcwd( drive, path, _MAX_PATH ) != NULL )

            printf( " (Current directory is %s)", path );



         if(0==_dos_getdiskfree(drive,&diskspace))

         {

             LM=(unsigned long)(diskspace.avail_clusters)

             *(unsigned long)(diskspace.sectors_per_cluster)

             *(unsigned long)(diskspace.bytes_per_sector)/1024/1024;

             printf( "    %ld MBytes free",LM);        

         }

         putchar( '\n' );

      }

   } 

   _chdrive( curdrive );  // Restore original drive.

}

// crt_getdiskfree.c

// compile with: /c

#include <windows.h>

#include <direct.h>

#include <stdio.h>

#include <tchar.h>



TCHAR   g_szBorder = _T("======================================================================\n");

TCHAR   g_szTitle1 = _T("|DRIVE|TOTAL CLUSTERS|AVAIL CLUSTERS|SECTORS / CLUSTER|BYTES / SECTOR|\n");

TCHAR   g_szTitle2 = _T("|=====|==============|==============|=================|==============|\n");

TCHAR   g_szLine   = _T("|  A: |              |              |                 |              |\n");



void utoiRightJustified(TCHAR* szLeft, TCHAR* szRight, unsigned uVal);



int main(int argc, char* argv) {

   TCHAR szMsg;

   struct _diskfree_t df = {0};

   ULONG uDriveMask = _getdrives();

   unsigned uErr, uLen, uDrive;



   printf(g_szBorder);

   printf(g_szTitle1);

   printf(g_szTitle2);



   for (uDrive=1; uDrive<=26; ++uDrive) {

      if (uDriveMask & 1) {

         uErr = _getdiskfree(uDrive, &df);

         memcpy(szMsg, g_szLine, sizeof(g_szLine));

         szMsg = uDrive + 'A' - 1;



         if (uErr == 0) {

            utoiRightJustified(szMsg+8,  szMsg+19, df.total_clusters);

            utoiRightJustified(szMsg+23, szMsg+34, df.avail_clusters);

            utoiRightJustified(szMsg+38, szMsg+52, df.sectors_per_cluster);

            utoiRightJustified(szMsg+56, szMsg+67, df.bytes_per_sector);

         }

         else {

            uLen = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL,

                            uErr, 0, szMsg+8, 4100, NULL);

            szMsg = ' ';

            szMsg = ' ';

            szMsg = ' ';

         }



         printf(szMsg);

      }



      uDriveMask >>= 1;

   }



   printf(g_szBorder);

}



void utoiRightJustified(TCHAR* szLeft, TCHAR* szRight, unsigned uVal) {

   TCHAR* szCur = szRight;

   int nComma = 0;



   if (uVal) {

      while (uVal && (szCur >= szLeft)) {

         if   (nComma == 3) {

            *szCur = ',';

            nComma = 0;

         }

         else {

            *szCur = (uVal % 10) | 0x30;

            uVal /= 10;

            ++nComma;

         }



         --szCur;

      }

   }

   else {

      *szCur = '0';

      --szCur;

   }



   if (uVal) {

      szCur = szLeft;



      while   (szCur <= szRight) {

         *szCur = '*';

         ++szCur;

      }

   }

}

结果如下，中间未提示错误信息，这样就好

======================================================================
|DRIVE|TOTAL CLUSTERS|AVAIL CLUSTERS|SECTORS / CLUSTER|BYTES / SECTOR|
|=====|==============|==============|=================|==============|
| C: | 7,681,070 | 5,276,989 | 8 | 512 |
| D: | 23,041,218 | 18,417,512 | 8 | 512 |
| E: | 23,041,218 | 16,398,257 | 8 | 512 |
| F: | 21,818,270 | 2,858,339 | 8 | 512 |
| G: | 2,560,351 | 2,543,733 | 8 | 512 |
| H: | 设备未就绪。 | | |
| I: | 设备未就绪。 | | |
======================================================================