Error in function nSerialHD ()

[StefanHaupt]

Antonio,

maybe I found an error in the function nSerialHD(). It always returns negative values.

If I change hb_retnl (..) to hb_retnll (..) it is working correct.

Code: Select all  Expand view

HB_FUNC( NSERIALHD )
{
   DWORD dwVolumeSerialNumber;
   BYTE VolumeNameBuffer[ 256 ];
   BYTE FileSystemNameBuffer[ 256 ];

   GetVolumeInformation( hb_pcount() ? hb_parc( 1 ): "C:\\",
                         ( char * ) VolumeNameBuffer, sizeof( VolumeNameBuffer ),
                         &dwVolumeSerialNumber, 0, 0,
                         ( char * ) FileSystemNameBuffer,
                         sizeof( FileSystemNameBuffer ) );

   hb_retnll( dwVolumeSerialNumber );   //<------
}


Can you check this, please

[Patrick Mast]

Antonio,

maybe I found an error in the function nSerialHD(). It always returns negative values.

If I change hb_retnl (..) to hb_retnll (..) it is working correct.

Code: Select all  Expand view

HB_FUNC( NSERIALHD )
{
   DWORD dwVolumeSerialNumber;
   BYTE VolumeNameBuffer[ 256 ];
   BYTE FileSystemNameBuffer[ 256 ];

   GetVolumeInformation( hb_pcount() ? hb_parc( 1 ): "C:\",
                         ( char * ) VolumeNameBuffer, sizeof( VolumeNameBuffer ),
                         &dwVolumeSerialNumber, 0, 0,
                         ( char * ) FileSystemNameBuffer,
                         sizeof( FileSystemNameBuffer ) );

   hb_retnll( dwVolumeSerialNumber );   //<------
}


Can you check this, please

Lets be carefull with this function. In my app for example, I use this function to activate my app on THIS HD. If this function suddenly returns a different number, my apps will all DE-activate.

Thanks.

Patrick

[Antonio Linares]

Stefan,

A negative value means a numeric value with the "sign bit" on (left most bit).

If you want it as a positive number, you just need to calculate the complementary number.

In other words: there are no "negative" numbers. The "sign bit" may be on or off, and then we can interpret it as we may need it.

I am not sure if I am quite clear about it

[Antonio Linares]

http://en.wikipedia.org/wiki/Sign_bit

http://encarta.msn.com/encyclopedia_762 ... umber.html

[Antonio Linares]

Stefan,

Your solution as a function:

Code: Select all  Expand view

function Main()

   MsgInfo( NoSign( HexToDec( "FFFFFFFF" ) ) )
   
return nil

#pragma BEGINDUMP

#include <hbapi.h>

HB_FUNC( NOSIGN )
{
   hb_retnll( ( unsigned long ) hb_parnl( 1 ) );
}

#pragma ENDDUMP


[StefanHaupt]

Lets be carefull with this function. In my app for example, I use this function to activate my app on THIS HD. If this function suddenly returns a different number, my apps will all DE-activate.

Patrick,

I see the problem, you (and maybe others) will get, changing this function. I discovered this issue comparing the return values of nSerialHD (FWH) and VolSerial (xHarbour). VolSerial() returns imho the right value.

It´s very confusing if two functions that do the same are returning different values.

[StefanHaupt]

Antonio,

thanks for your explanation, you are right, in computer numbering there are no negative values.

Your solution overcomes any problem concerning existing applications using this function for protection.

But nevertheless it is very confusing if two functions with the same functionality return different values (comparing nSerialHD() and HexToDec() with VolSerial() and HexToNum() from xHarbour)

[Antonio Linares]

Stefan,

The problem comes from the fact that in 32 bits hb_retnl() is unable to return an unsigned number (from a certain values range).

Using the function NoSign() we can easily solve it and we can keep backwards compatibility

[StefanHaupt]

Using the function NoSign() we can easily solve it and we can keep backwards compatibility

Yes, I agree

[Patrick Mast]

Using the function NoSign() we can easily solve it and we can keep backwards compatibility

But this still changes the return value correct? So, my save HD serial nr will not be valid anymore?

Patrick

[Antonio Linares]

Patrick,

We are not modifying nSerialHD() at all

So we keep full backwards compatibility. function NoSign() is there for those that want such value without sign.