Re: Writing/Reading binaric objects to/from a file - C / C++ / MFC Discussion Boards

Re: template problems

Joaquín M López Muñoz7-Oct-04 2:38

Joaquín M López Muñoz

7-Oct-04 2:38

Oh, also, you don't really need the <int> part here. The following should suffice:

void MyFunc(int value)
{
objectPointer->SetCellStyle(row, column, value);
}

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
Want a Boost forum in Code Project? Vote here[^]!

Re: template problems

pankajdaga7-Oct-04 10:44

pankajdaga

7-Oct-04 10:44

Hi!

Thanks. The whole problem was the <int> in the call. It behaves ok when I use

objectPointer->SetCellStyle(row, column, value) instead of
objectPointer->SetCellStyle<int>(row, column, value);

I have no idea why. I thought after VS 5.0 this problem disappeared. I am going to try it with VS 7 to see what happens.

Cheers,
Pankaj

<font size = "1">
/**
I'm the one who's gonna have to die
When it's time for me to die
So let me live my life
The way I want to
- Jimi Hendrix
*/</font>

Debugging DLL project in VC++ 6.0

Neeranjan7-Oct-04 1:51

Neeranjan

7-Oct-04 1:51

Hi,
I have two projects
1. DLL project: Creating one .dll file
2. Application project: Which uses the .dll file created in Dll project

First I execute the Dll Project in Debug mode wherein it creates a .dll file. Now I copy this .dll file to the Debug folder of Application project. Now I execute the Application project in debug mode which uses the created .dll file.
How can I debug the DLL project (traversing .cpp files of DLL project by puting break points) i.e. I put a break point into a CPP file(X) of DLL Project and one break point in the CPP file(Y) of Applicatin project where it calls the function from dll file. When control reaches the break point in Y which calls to the function in dll file and if I press F5, control should go to the function in CPP file (X) of DLL project.

How to do this?

Thanks & Regards,
Neeraj

Re: Debugging DLL project in VC++ 6.0

Roger Allen7-Oct-04 7:13

Roger Allen

7-Oct-04 7:13

Insert the DLL project into .exe workspace from the projects menu
Set the exe project as active configuration
Make the exe project dependent on the dll project (porject dependencies)
Add a post build step to the dll project which copies the nuilt dll to the applications directory
Place breakpoints as required (works as VC knows about both)
Debug as required.

If you vote me down, my score will only get lower

Writing/Reading binaric objects to/from a file

impeham7-Oct-04 1:46

impeham

7-Oct-04 1:46

I need to save few objects' to a file and reload them later on to memory.
I used something like that:

WriteFile(hFile, obj_ptr, sizeof(DATABASEINFO), &NumberOfBytesWritten, NULL);

and then:

ReadFile(hFile, CurrentObject, sizeof(DATABASEINFO), &NumberOfBytesRead, NULL);

where "CurrentObject" is a pointer to an allocated space for "DATABASEINFO" structure.

This method doesn't work. the Read operation reads nonsense.

Can anyone see the problem? is there a better way for doing this?

Thanks.

Re: Writing/Reading binaric objects to/from a file

Cedric Moonen7-Oct-04 2:19

Cedric Moonen

7-Oct-04 2:19

Make sure the structure members are on 1 byte boundaries. You can specify that using:

#pragma pack(1)
macro.

You can also specify it for complete project in project -> settings, C/C++ tab and there choose the Code generation category and set struct member alignment to 1 byte.

Re: Writing/Reading binaric objects to/from a file

impeham7-Oct-04 2:45

impeham

7-Oct-04 2:45

ok. it seems to do the work. but there is still a problem with pointers types. is there a simple way to handle them?

for example, in one structure i am holding a property from type char*. when writing the object to the file, the pointer is stored and not the string held in it, which is, of course - useless.

Re: Writing/Reading binaric objects to/from a file

Cedric Moonen7-Oct-04 3:03

Cedric Moonen

7-Oct-04 3:03

Of course, you cannot use this when your structure hold pointers !!! WTF | :WTF:

What is a pointer ? A pointer is just a 32 bits variable that holds an adress (at this adress, the data is stored). So, when you write the pointer to the file, it just stores the adress and not the data.

If you want to save your structure, it would be a better idea to encapsulate the save/load functions inside your structure (if you don't use the MFC and/or don't want to use serialisation, you can do it yourself):

typedef struct
{
   int DataCount;
   int* pSomeData;

   void SaveData(HANDLE* hFile)
   {
      DWORD NumberOfBytesWritten;
      WriteFile(hFile, &DataCount, sizeof(int), &NumberOfBytesWritten, NULL);
      WriteFile(hFile, pSomeData, sizeof(int)*DataCount, &NumberOfBytesWritten, NULL);
   }

   void LoadData(HANDLE* hFile)
   {
      DWORD NumberOfBytesRead;
      ReadFile(hFile, &DataCount, sizeof(int), &NumberOfBytesRead, NULL);
      pSomeData = new int[DataCount];
      ReadFile(hFile, pSomeData, sizeof(int))*DataCount, &NumberOfBytesRead, NULL);
   }
} YourStruct;

And from the outside it will look like:

YourStruct* pStruct = new YourStruct;
//Do something with pStruct
//..
//..
pStruct->SaveData(hFile);

Or for loading:

YourStruct* pStruct = new YourStruct;
pStruct->LoadData(hFile);
//Do something with pStruct
//..
//..

Hope this helps

Re: Writing/Reading binaric objects to/from a file

Ravi Bhavnani7-Oct-04 2:23

Ravi Bhavnani

7-Oct-04 2:23

See this[^] article.

/ravi

My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com

Data Sharing

shiraztk7-Oct-04 0:49

shiraztk

7-Oct-04 0:49

Hi all

How can I share some memory allocated in one process by another process by using dll.?
Is there any way to accomlish this using other methods

Thanks in advance

The Best Relligion is Science.
Once you understand it, you will know God.

Re: Data Sharing

Cedric Moonen7-Oct-04 1:12

Cedric Moonen

7-Oct-04 1:12

Maybe you can use memory-mapped files ? You can open a file-mapping object in memory from one process and access data in it within another process.
Take a look at the MSDN for file mapping (and file mapping functions...)

Hope this helps

Re: Data Sharing

Blake Miller7-Oct-04 11:07

Blake Miller

7-Oct-04 11:07

Or...even look more locally...

http://www.codeproject.com/threads/ipc_tute.asp

http://www.codeproject.com/win32/cmemmap.asp

http://www.codeproject.com/threads/csharedstruct.asp

http://www.codeproject.com/threads/sm.asp

http://www.codeproject.com/threads/sharedmemipc.asp

http://www.codeproject.com/threads/memmapipc1.asp

http://www.codeproject.com/threads/SharedMemory_IPC_Threads.asp

That should get you pointed in the right direction Cool | :cool:

Re: Data Sharing

jan larsen7-Oct-04 1:22

jan larsen

7-Oct-04 1:22

The recommended way to share data, is memory mapped files. Look up the functions CreateFileMapping and MapViewOfFile.

You could also create a shared section in your dll, I can't remember the procedure, but you should be able to find it on MSDN by searching for '#pragma' and 'shared'.

I don't think you can share memory allocated by new() or malloc() though...

"After all it's just text at the end of the day. - Colin Davies

"For example, when a VB programmer comes to my house, they may say 'does your pool need cleaning, sir ?' " - Christian Graus

Re: Data Sharing

shiraztk7-Oct-04 19:40

shiraztk

7-Oct-04 19:40

Hi
Thank you all, it was of great help.
See you all later Smile | :)

bye

The Best Relligion is Science.
Once you understand it, you will know God.

Converting CString

Franz Klein7-Oct-04 0:07

Franz Klein

7-Oct-04 0:07

I am using Visual Studio .NET 2003.
I would like to convert a CString into a std::string. With Visual C++ Ver 6.0 one could just use the std::string constructor, but now I get an error message with VS .NET 2003. Does anybody know?
Cry | :((

I am the handsome one in the crowd.

Re: Converting CString

Joaquín M López Muñoz7-Oct-04 2:40

Joaquín M López Muñoz

7-Oct-04 2:40

Maybe forcing the conversion to a LPCSTR?

Cstring cs=...;
std::string s=(LPCSTR)cs;

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
Want a Boost forum in Code Project? Vote here[^]!

Socket Programming using threads

Ajoy6-Oct-04 23:29

Ajoy

6-Oct-04 23:29

Scenario :- I want to connect to multiple servers from a single client at a time and collect some information.

Is it possible to do this using CAsyncSocket in a single thread for each server?

When is CAsynSocket used instead of CSocket ?

Thanks in Advance,
Ajoy.

U Live And Let Others Live Smile | :)

Re: Socket Programming using threads

Sujan Christo7-Oct-04 0:49

Sujan Christo

7-Oct-04 0:49

Hi,
Be carefull with multithreading, CLOSING, I've experinced the pain.PLAN PROPERLY.
Sujan

Re: Socket Programming using threads

Bob Stanneveld7-Oct-04 2:46

Bob Stanneveld

7-Oct-04 2:46

Hello,

MSDN says the following about CSocket and CASyncSocket:
"You should probably consider using CAsyncSocket if you want Windows Sockets' ease of dealing with multiple network protocols in an MFC application but do not want to sacrifice flexibility. You might also feel that you can get better efficiency by programming the communications more directly yourself than you could using the more general alternative model of class CSocket."

So CSocket is a more easy to use class at the cost of some overhead. If you don't need high speed connections, multi network protocols, I'd stick with CSocket.

Hope this helps Big Grin | :-D

Multiply it by infinity and take it beyond eternity and you'll still have no idea about what I'm talking about.

Re: Socket Programming using threads

vcplusplus7-Oct-04 3:02

vcplusplus

7-Oct-04 3:02

I have heard that there are problems with CSocket.
Check out this article.
http://tangentsoft.net/wskfaq/articles/csocket.html[^]

Re: Socket Programming using threads

Bob Stanneveld7-Oct-04 3:11

Bob Stanneveld

7-Oct-04 3:11

I didn't knew that..
Als an alternative, you can use a Socket class found here on codeproject. There are many here, so it should be easy to find one.

Multiply it by infinity and take it beyond eternity and you'll still have no idea about what I'm talking about.

DIID_HTMLElementEvents2

george ivanov6-Oct-04 22:50

george ivanov

6-Oct-04 22:50

I'm using code from MSDN article "Handling HTML Element Events" but DIID_HTMLElementEvents2 interface seems to be undefined.
It's not declared in mshtml.h, only DIID_HTMLElementEvents.
Where is DIID_HTMLElementEvents2 declared?

were rgrtgrtvrtrt rtrtb brt tyuhjghj hbhbnh hnjm 1234567?

VC and Crystal Report

TrungHuynh6-Oct-04 22:27

TrungHuynh

6-Oct-04 22:27

I have write an application, use VC++ connect to Oracle database, and use Crystal Report to view data and print

Any one can help me, how to connect to Oracle and use Crystal report.
thanks.

Re: VC and Crystal Report

Member 14198776-Oct-04 23:43

Member 1419877

6-Oct-04 23:43

The same problem i also have, but instead of Oracle database i am using MS Access as the database. Can Anybode let me know how to get the same thing using MS Access as the database.

I know how to connect to MS Acces database, but what i want to know is how to use Crystal Report to view data and print.

Regards,

Pankaj

Re: VC and Crystal Report

Jose Cezar S. Ynion7-Oct-04 1:47

Jose Cezar S. Ynion

7-Oct-04 1:47

VC++ fronend, MS Access backend with Seagate Crystal Report sample code can be downloaded at

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.