C / C++ / MFC

Implementing queues along with threads

10-Mar-09 4:25

Are you referring to the LVS_OWNERDRAWFIXED style?

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Re: Custom listcontrol

Hamid_RT10-Mar-09 5:02

Hamid_RT

10-Mar-09 5:02

Yes [^].

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

kr_ash10-Mar-09 3:21

kr_ash

10-Mar-09 3:21

Hi all,
my requirement is there is a function which creates one thread and passes the data for further processing which looks like
void MyFunc(char *data)
{
CreateThread(NULL,0,build_data,(void *)data,0,NULL);
}
Now i want to modify the above code.
I want to introduce a queue class and want to create two threads so that 1st thread can invoke a function which writes the data to the queue and the 2nd thread reads the data from the queue. Please introduce mutex if required. Can you tell me how to implement the above in VC++.
Please help me on the above. Thanks

Re: Implementing queues along with threads

David Crow10-Mar-09 3:59

CFile output - Problem - An extra White space

10-Mar-09 3:59

kr_ash wrote:
...1st thread can invoke a function which writes the data to the queue and the 2nd thread reads the data from the queue.

This sounds a bit like the producer/consumer problem.

PankajB10-Mar-09 2:49

PankajB

10-Mar-09 2:49

Hi there.

I am writing a string into a .txt file, but I am getting an extra while space in between each char.
Please suggest me, why this is so.

For Eg. if I write Hello, it will be written as H e l l o.

Thanks
PanB

Iain Clarke, Warrior Programmer10-Mar-09 3:01

10-Mar-09 3:01

I'm going to put on my psychic hat...

You are not getting a space between letters, you are getting a NULL.

Your text in the compiler is a TCHAR, and that defaults to unicode these days.

You're looking at the text in notepad, and it's reading it as ascii...

Read:
http://www.codeproject.com/KB/string/cppstringguide1.aspx[^]

You will be a better person afterwards, and will no longer kick puppies for fun.

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

CPallini10-Mar-09 3:29

CPallini

10-Mar-09 3:29

Well, welcome again in the CP's Memorable Quotes list [^].
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Sarath C10-Mar-09 3:15

Sarath C

10-Mar-09 3:15

If your're passing string something like this, _T("Hai"), according to the unicode settings of project, the string will be treated as unicode characters which means two bytes per character. That's the reason for this issue.

CFile::Write will take any kind of inputs. If you've the string with you,
you can writes as file1.Write( "Hai", 3 ); or convert using WideCharToMultibyte API or W2A conversion macros and then write the file.

If you want to write and save the file as unicode text file, then you will have to add BOM characters before writing to file.
Check this article[^]

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

David Crow10-Mar-09 3:43

Re: Database with password

10-Mar-09 3:43

PankajB wrote:
I am writing a string into a .txt file, but I am getting an extra while space in between each char.
Please suggest me, why this is so.

See here.

Database with password

Grebeshkova10-Mar-09 1:56

Grebeshkova

10-Mar-09 1:56

Hello,
ask to help me with 2 problems.
Access-database has password and open by
try
{
hr = m_pConnection->Open(_bstr_t (lpstrConnection), ...);
return hr == S_OK;
}
catch(_com_error &e)
{}
1) When database file has attribute "ReadOnly" catch takes place with NativeError=0xfffff88f and NumberError=80004005 ("Not a valid password").
But when ja reset attribute "ReadOnly", database is opened OK. Why error is detected for Readonly file?
2) How can I recognize that invalid password is in connection string? Which code will be in NativeError for any database type (not only Access)in this case?

Thanks

David Crow10-Mar-09 3:45

10-Mar-09 3:45

Grebeshkova wrote:
1) When database file has attribute "ReadOnly"...

Is it readonly at the OS level or at the application (i.e., Access) level?

map in mfc

hrishiS10-Mar-09 1:41

hrishiS

10-Mar-09 1:41

Hi to everyone,

I am breaking my head to find a proper example how to use map of STL in mfc. But didnt get.
Could anyone please help me out with the same. Please give me the exact syntax to use them.

I want to create a map with 3 fields (like a table)

id, name, RegNo

thanks in advance

I am a beginner

Iain Clarke, Warrior Programmer10-Mar-09 1:47

10-Mar-09 1:47

I think a map is between one thing (key) and another thing (object). [*]

But you could package the name and regno in a structure together, then map between the id and otherstuffstruct...

Iain.

[*] someone will now say "but in boost..."

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Nishad S10-Mar-09 2:38

Nishad S

10-Mar-09 2:38

himangshuS wrote:
how to use map of STL in mfc

Confusing... In MFC there is a map template class named CMap.

- ns ami -

CPallini10-Mar-09 3:01

CPallini

10-Mar-09 3:01

As suggest by Iain, you may use a struct, for instance, assuming id unique (see, for instance, [^]):

#include <map>
using namespace std;
struct MyData
{
  string _name;
  int _regNo;
  MyData(string name, int regNo): _name(name), _regNo(regNo){}
};

void main()
{
  map <int, MyData> mymap;
  mymap.insert(pair <int, MyData>(1, MyData("foo", 10)));
}

BTW MFC hai is own CMap container, but keep away from it!

Eytukan10-Mar-09 6:46

Eytukan

10-Mar-09 6:46

Or this way too.

std::map<int,pair><string,int> > myMap;
myMap[10] = make_pair("cp",10);

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Stephen Hewitt10-Mar-09 3:06

Stephen Hewitt

10-Mar-09 3:06

Using STL's std::map from MFC is no different from using it anywhere else. See here[^] for an example.

Steve

http://www.codeproject.com/script/Forums/View.aspx?fid=1647&msg=2958324[^]

Eytukan10-Mar-09 6:50

Eytukan

10-Mar-09 6:50

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Different encoding??

gothic_coder10-Mar-09 1:03

gothic_coder

10-Mar-09 1:03

Sorry for my repeat post as my previous post crosses so many pages...

I'll explain my problem once again...

I've one database which includes chinese and english character... Now extracting from the database is done..with the help of connection object and query and all other thing..That's not the issue...

Now when i extract the part (Field) which contains both english and chinese character with the help of this..

_bstr_r  bstrString_Dest;
bstrString_Dest= m_cpRecordsetSearch->Fields->GetItem("DestinationValue")->GetValue().bstrVal;

Now when i see using quick watch or tool tip it comes "abc??????" question marks are actually chinese character...

Now i do this to write into the file...

stream = fopen(pszwritepath, "ab");
if(stream == NULL)
{
   return 0;
}

int n = fwprintf(stream, L"%ls\r\n", (wchar_t*)bstrString_Dest);

It comes to notepad as "abc(aquare brackets)"... Now when i copy the text from notepad and paste to MS-Word or MS-Access it shows perfectly.. i.e "abc(chinese character)"... But when i see same file on chinese machine it shows junk character...

So where am i going wrong?? Is there something encoding compatibility of notepad in my machine and chinese machine?? I'm really stuck in here...

Iain Clarke, Warrior Programmer10-Mar-09 1:43

10-Mar-09 1:43

VC++ is not good at showing you the chinese text. I assume the characters are not in the font it uses. This does not mean the code is bad.

Notepad is just guessing at the encoding, and getting it wrong.

But if you're saving UNICODE, you can help notepad by saving a byte order marker (or BOM) at the front of the file.

I forget it should be FFFE, or FEFF. But as that's only two choices, try both and see which works.

You possibly will also have the problem of fonts having the chinese characters in it in notepad.

Good luck,

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

gothic_coder10-Mar-09 1:45

gothic_coder

10-Mar-09 1:45

All right i get it...

stream = fopen(pszwritepath, "ab");
if(stream == NULL)
{
   return 0;
}

int n = fwprintf(stream, L"%ls\r\n", (wchar_t*)bstrString_Dest);

Above code is working perfectly... I wasn't selecting unicode while i was seeing in notepad (Silly mistake)... But as i've to make many file how do i make sure that the data which is being writed to notepad open as unicode only not ascii???

Thanks

P.S
Didn't saw ian's post.. Thanks i'll try to do that..
You mean to say before i write to the file i should write that byte order marker (BOM) first???

Iain Clarke, Warrior Programmer10-Mar-09 2:14

10-Mar-09 2:14

gothic_coder wrote:
You mean to say before i write to the file i should write that byte order marker (BOM) first???

Yes. See:
http://en.wikipedia.org/wiki/Byte-order_mark[^]

As for mispelling my name... As you're not from the mother country, I'll forgive you. Once. Please warn all of your fellow countrymen to not make the same mistake...

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...