Problem with DWORD

[Guest_imported]

Hallo,

I have the following C++ code:


typedef struct tagIOCTLParams
{
DWORD dioc_IOCtlCode;
PVOID dioc_InBuf;
} IOCTLPARAMS, *PIOCTLPARAMS;

...
PIOCTLPARAMS p;
char buf[128];

_snprintf (buf, 128,
"IOCTL is: %i",
p->dioc_IOCtlCode);

But %i seemed to be wrong, because I get a value like "-1475374670" instead of "-2080374773".

What have I done wrong?

Bye Tim

 

[Pavlo]

Greetinx!

Here your code:
PIOCTLPARAMS p;
char buf[128];
_snprintf (buf, 128, "IOCTL is: %i", p->dioc_IOCtlCode);
and where are you allocate memory for IOCTLPARAMS structure?
So if not you must allocate memory and define parameters of the structure.




Happy programming!))

 

[jinappa]

Also, is 128 bytes right? Once you have allocated the memory for the structure, if it is still wrong, I would check the math there. that looks fishy to me.

Good Luck..

 

[Guest_imported]

Hallo,

thank you for reply, but there is no need to allocate memory, it seems that it is done automatically.
Now I found out "%i" is wrong because DWORD is unsigned and so you had to use "%u".

The next problem I have is that the code:

typedef struct tagIOCTLParams
{
PCLIENT_STRUCT dioc_pcrs;
VMHANDLE dioc_hvm;
DWORD dioc_VxdDDB;
DWORD dioc_IOCtlCode;

PVOID dioc_InBuf;

DWORD dioc_cbInBuf;
PVOID dioc_OutBuf;
DWORD dioc_cbOutBuf;
PDWORD dioc_bytesret;
OVERLAPPED* dioc_ovrlp;
DWORD dioc_hDevice;
DWORD dioc_ppdb;
} IOCTLPARAMS, *PIOCTLPARAMS;

.. and the method I try to analyse "dioc_InBuf" isn't right as well. "%s" and the sructure of "dioc_InBuf" seemed to be wrong in the following code:

_snprintf (buf, 128,
"dwIoCtrlCode: %u\t lpInBuf: %s\t lpOutBuf %s\t lpdBytesRet: %d\n",
p->dioc_IOCtlCode,

p->dioc_InBuf,

p->dioc_OutBuf,
p->dioc_bytesret);

"InBuf" seemed not be a string (I just get values like "o0_*..." - maybe it's a structure like this EXAMPLE:

#pragma pack(1)
typedef struct {
ULONG seq;
char text[32];
} ENTRY, *PENTRY;
#pragma pack()
...

PENTRY->seq = 1;
PENTRY->text = 'hallo;

p->dioc_InBuf = PENTRY;


Now it's the question if it is possible to get the structure of "p->dioc_InBuf", that means the right struture of PENTRY?


Bye Tim