C / C++ / MFC Discussion Boards

Re: File Property

David Crow31-Mar-04 2:07

David Crow

31-Mar-04 2:07

Are you talking about GetFileAttributes()?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: File Property

hb.sapto nugroho31-Mar-04 3:07

hb.sapto nugroho

31-Mar-04 3:07

I am not sure if file owner and
file acess authority (readonly, readwrite,etc)
are in GetFileAttributes.

If the properties that I mean are also
can be taken by GetFileAttributes,
then tell me how to coding it.

regards

Re: File Property

David Crow31-Mar-04 3:46

David Crow

31-Mar-04 3:46

hb.sapto nugroho wrote:
I am not sure if file owner and
file acess authority (readonly, readwrite,etc)
are in GetFileAttributes.

Use GetNamedSecurityInfo() and LookupAccountSid() for owner. Use GetFileAttributes() for the other two.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: File Property

hb.sapto nugroho31-Mar-04 15:52

hb.sapto nugroho

31-Mar-04 15:52

dear David

thanks for helping me.
I found difficulty in real coding.
Would you mind to write the sample coding of it.

I found error:
GetNamedSecurityInfo is not member of global namespace
also for LookupAccountSid.

looking your help
hb.sapto nugroho

Re: File Property

David Crow1-Apr-04 3:12

David Crow

1-Apr-04 3:12

hb.sapto nugroho wrote:
I found difficulty in real coding.

Does that imply there is "fake" coding?

hb.sapto nugroho wrote:
GetNamedSecurityInfo is not member of global namespace
also for LookupAccountSid.

How are you using them?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

How to take screenshots

Anonymous30-Mar-04 23:24

Anonymous

30-Mar-04 23:24

How to take screenshots from the VC program?

Re: How to take screenshots

Uwe Keim31-Mar-04 1:26

Uwe Keim

31-Mar-04 1:26

Pressing the Alt+PrtScr keys simultaneously.

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Re: How to take screenshots

Alexander ^M.,31-Mar-04 2:01

Alexander ^M.,

31-Mar-04 2:01

Don't try it, just do it! Wink | ;-)

Re: How to take screenshots

Prakash Nadar31-Mar-04 5:06

Prakash Nadar

31-Mar-04 5:06

Nonsence answer.

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Re: How to take screenshots

Anonymous31-Mar-04 7:56

Anonymous

31-Mar-04 7:56

Thanks, u got me right

Re: How to take screenshots

David Crow31-Mar-04 2:11

David Crow

31-Mar-04 2:11

See if either of these two articles help:

http://flounder.com/screencapture.htm
http://flounder.com/printbitmap.htm

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: How to take screenshots

Anonymous31-Mar-04 7:58

Anonymous

31-Mar-04 7:58

Thanks a lot, u read me well, I will check it an let u know

Convert C++ DLL to VB.net Help

nelsonbd30-Mar-04 22:53

nelsonbd

30-Mar-04 22:53

Hi,

I am struggling to convert some functions from a C++ DLL to some function references in VB.net
I dont program in C++, so I am hoping someone can help me with converting a couple of function prototypes:

This are the C++ prototypes:

CP2101_Open(DWORD dwDevice, HANDLE* cyHandle);

CP2101_GetProductString(DWORD dwDeviceNum, LPVOID lpvDeviceString, DWORD dwFlags);

CP2101_Close(HANDLE cyHandle );

This is what i have in vb.net:

Public Declare Function CP2101_Open Lib "CP2101.dll" (ByVal DeviceNum As Long, ByRef Handle As Long) As Integer

Public Declare Function CP2101_GetProductString Lib "CP2101.dll" (ByVal DeviceNum As Long, ByRef DeviceString As String, ByVal Options As Long) As Integer

Public Declare Function CP2101_Close Lib "CP2101.dll" (ByVal DeviceNum As Long) As Integer

I am not sure that I am converting the pointer data types correctly etc from C++ to Vb.net. If some could check my work.

Thanks

Barry

Re: Convert C++ DLL to VB.net Help

Antony M Kancidrowski31-Mar-04 0:38

Antony M Kancidrowski

31-Mar-04 0:38

What problems are you experiencing here?

The VB declarations look OK to me. Smile | :)

Ant.

Re: Convert C++ DLL to VB.net Help

Alexander ^M.,31-Mar-04 2:04

Alexander ^M.,

31-Mar-04 2:04

These
nelsonbd wrote:
This are the C++ prototypes:
not true!

These are C prototypes, else they would have very crazy export names in C++ name convention!

Don't try it, just do it! Wink | ;-)

Re: Convert C++ DLL to VB.net Help

antlers31-Mar-04 6:54

antlers

31-Mar-04 6:54

The potential problem I see is in interpreting the LPVOID DeviceString as a ByRef String. If I remember my VB right, a ByRef String is passed to a C function as a pointer to BSTR. That may not be (probably is not) what the C function is expecting.

An LPVOID doesn't give very much information about what it is expecting: it could be a null-terminated string, a null-terminated wide-string, a BSTR or perhaps a pointer to BSTR. Do you have source for that C function, or a C example of its use?

Re: Convert C++ DLL to VB.net Help

Mike Dimmick31-Mar-04 12:51

Mike Dimmick

31-Mar-04 12:51

Firstly, you should normally use System.IntPtr for opaque pointer types when using VB.NET. This will help you if you ever port to 64-bit (the IntPtr type is 32 bit in a 32-bit process but 64 bits in a 64-bit process).

As for CP2101_GetProductString, if the C/C++ code is interpreting the lpvDeviceString parameter as a string, you should use

Public Declare Function CP2101_GetProductString Lib "CP2101.dll" ( _
  ByVal DeviceNum As Long, _
  ByVal DeviceString As String, _
  ByVal Options As Long) As Integer

ByRef indicates an in/out parameter. If the function alters this data, you should use a StringBuilder object instead (still passed ByVal), and set its Capacity to the maximum size you expect the function to write.

If you're getting MissingMethodExceptions, your DLL's exports may be mangled. To verify this, use dumpbin /exports. If the output contains ? characters and no recognisable function names, the names are mangled. You have two choices. Either you can rewrite your declarations to use the DllImportAttribute rather than Declare, and use the EntryPointName property to indicate the mangled name, or you can specify extern "C" in front of the exported function declarations to tell the compiler not to mangle the names. Remember that the latter will break binary compatibility with any existing clients.

Stability. What an interesting concept. -- Chris Maunder

copy constructor / assignment operator

GDavy30-Mar-04 22:48

GDavy

30-Mar-04 22:48

Hi guys,

A question:
I got a class A that has a overridden copy constructor and assignment operator.
I derive class B from A.

*If B does not have an overridden copy constructor or assignment operator will the assignments of objects of class B invoke the copy constr. or assign operator of class A for the A part of class B(if you know what I mean)?

eg:

class A
{
class A();
class A( const A& a);
A& operator=(const A& a);
...
};

class B: public A
{
...
};

int main()
{
B obj1, obj2;
...
obj2 = obj1; //is operator= of class A called?
B obj3 = obj2; // is copy construct of class A called?
}

Greetings,
Davy

Re: copy constructor / assignment operator

22491730-Mar-04 23:13

224917

30-Mar-04 23:13

no, you ll have to modify like this

B obj1;
A obj2;

obj2 = obj1; //operator= of class A is called
A obj3 = obj2; //copy construct of class A is called

but remember ur objects will have to be sliced..

greatest thing is to do wot others think you cant
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Re: copy constructor / assignment operator

Prakash Nadar31-Mar-04 5:04

Prakash Nadar

31-Mar-04 5:04

Suhredayan P wrote:
ur objects will have to be sliced..

woah whats that ? OMG | :OMG:

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Re: copy constructor / assignment operator

David Crow31-Mar-04 2:14

David Crow

31-Mar-04 2:14

Can you set a breakpoint on the line(s) in question to see what happens?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

random number

shiva shankar30-Mar-04 22:21

shiva shankar

30-Mar-04 22:21

Can someone pls provide me with an algorithim that generates an random number ( 0 to 1000)and it cannot generate the same random number more than once.

Re: random number

SJolly30-Mar-04 23:11

SJolly

30-Mar-04 23:11

The output wouldn't be a random number as you are affecting the outcome, however to generate random numbers:

// seed the random number generator using the current time
srand((unsigned)time(NULL));

// gets a random number between 0 and 0x7fff
int iRandom = rand();

// scale this number down to a value between 0 and 1000.
iRandom /= (RAND_MAX / 1000);

Regards,
Simon

Re: random number

shiva shankar30-Mar-04 23:28

shiva shankar

30-Mar-04 23:28

thanks for your replay Mr.simon

but with // seed the random number generator using the current time
srand((unsigned)time(NULL));

the number will be repeated, but for me numbers shouldn't repeated in same sequence .

Re: random number

Antony M Kancidrowski30-Mar-04 23:49

Antony M Kancidrowski

30-Mar-04 23:49

You could hold all generated random numbers in a vector and check that the next number has not been used previously. If it has call the random again.

As long as you only want a few, i.e small percentage of the possible 1000 pseudo random numbers in your sequence, this will suffice.

Ant.

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