PRODUCT  :  Borland C++                           NUMBER  :  1704
  VERSION  :  3.X
       OS  :  WIN, DOS
     DATE  :  October 25, 1993                         PAGE  :  1/4

    TITLE  :  Detecting whether SHARE is loaded




  //--------------------------------------------------------------
  //
  //  Due to complications under Windows 3.x, SHARE can no longer
  //  be detected with certainty using int 2Fh Function 1000h.
  //
  //  The published workaround is to create a temporary file,
  //  and try to lock a section of it.  If the lock fails due
  //  to an "Invalid function number" (i.e. dos error code 1 )
  //  then SHARE is not loaded.
  //
  //  The following source is an example of doing this in C++.
  //  The source was designed for the large memory model, but
  //  can be compiled for the small memory model by modifying
  //  CreateTempOn() as indicated in the source.
  //
  //
  //  NOTE: The directory on which the shared files are located
  //        is significant in a network environment.  Typically
  //        share is loaded on the network server and is available
  //        for files on network drives.  This is not necessarily
  //        true for local drives.
  //--------------------------------------------------------------

  #include <errno.h>     // for errno and EINVAL
  #include <io.h>        // for lock()
  #include <string.h>    // for strlen() and strcpy()
  #include <iostream.h>  // for cout


  char *TempFilename;
  int DetectShareOn( char *PathToSharedFiles );
  int CreateTempOn( char *PathOfTempFile );
  int DeleteTempFile( void );


  int main(void)
     {
     char Directory[] = "C:\\";
     switch ( DetectShareOn ( Directory ) )
         {
         case 1:
             cout << "Share installed on " << Directory << endl;
             return 0;













  PRODUCT  :  Borland C++                           NUMBER  :  1704
  VERSION  :  3.X
       OS  :  WIN, DOS
     DATE  :  October 25, 1993                         PAGE  :  2/4

    TITLE  :  Detecting whether SHARE is loaded




         case 0:
             cout << "Share not installed on " << Directory
                  << endl;
             return 1;

         default:
             cout << "Error in detection." << endl;
             return 2;
         }
     }


  int DetectShareOn( char *PathToSharedFiles )
  // Parameter:
  //     PathToSharedFiles - null-terminated string containing
  //                         path to shared files
     {
     int RetValue;
     int TempHandle = CreateTempOn( PathToSharedFiles );
     if ( !TempHandle )
         return -1;

     switch (lock( TempHandle, 0, 1 ))
         {
         case -1:
             if ( errno == EINVAL )
                 RetValue = 0;
             else
                 RetValue = -1;
             break;

         default:
             unlock ( TempHandle, 0, 1 );
             RetValue = 1;
         }

     DeleteTempFile();
     return RetValue;
     }


  int CreateTempOn( char *PathOfTempFile )
  // Parameter:













  PRODUCT  :  Borland C++                           NUMBER  :  1704
  VERSION  :  3.X
       OS  :  WIN, DOS
     DATE  :  October 25, 1993                         PAGE  :  3/4

    TITLE  :  Detecting whether SHARE is loaded




  //     PathOfTempFile - null-terminated string containing
  //                      path to create temporary file
     {
     TempFilename = new char [ strlen(PathOfTempFile) + 13 ];
     if ( !TempFilename )
         return 0;
     strcpy( TempFilename, PathOfTempFile );

  asm    push    ds
  asm    xor     cx, cx
  asm    mov     dx, word ptr TempFilename

     // Remove the following two lines for near memory models
  asm    mov     ax, word ptr TempFilename + 2
  asm    mov     ds, ax

  asm    mov     ax, 5a00h
  asm    int     21h
  asm    pop     ds
  asm    jc      CreateTempFailed
     return (_AX);

  CreateTempFailed:
     return 0;
     }


  int DeleteTempFile( void )
     {
     int RetValue = remove ( TempFilename );
     switch ( RetValue )
         {
         case 0:
             delete TempFilename;
             return RetValue;

         default:
             return RetValue;
         }
     }
















  PRODUCT  :  Borland C++                           NUMBER  :  1704
  VERSION  :  3.X
       OS  :  WIN, DOS
     DATE  :  October 25, 1993                         PAGE  :  4/4

    TITLE  :  Detecting whether SHARE is loaded




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