C / C++ / MFC

16-Jan-06 1:45

I tried passing a CString variable (known to contain text) to a function, and inside the called function, the parameter I passed in is empty. Did something fundamental in CString change? Is there a compiler bug? Am I suddenly incapable of writing even the most simple code?

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

toxcct16-Jan-06 2:17

16-Jan-06 2:17

any sample to show us ? because i just don't understand the problem...

TOXCCT >>> GEII power
[toxcct][VisualCalc 2.20][VisualCalc 3.0]

#realJSOP16-Jan-06 2:43

16-Jan-06 2:43

void ThisFunction()
{
    CString myString = "test";
    MyFunction(myString);
}

void MyFunction(CString sVal)
{
    if (sVal.IsEmpty())
    {
       AfxMessageBox("Empy String");
    }
    else
    {
       AfxMessageBox(sVal);
    }
}

In the example above,m I get the message "Empty String".

Like I said, simple code - unexpected result.

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

toxcct16-Jan-06 2:51

16-Jan-06 2:51

and forcing the string to display in a message box (or directly with the debugger), is the string actually empty too? or is it just the .IsEmpty() function which is bugged ?

TOXCCT >>> GEII power
[toxcct][VisualCalc 2.20][VisualCalc 3.0]

#realJSOP16-Jan-06 3:11

16-Jan-06 3:11

The string is actually empty (in the debugger) before it gets to the comparison.

The project is an imported VC6 project. This is in a new class that I created using the IDE. I have other classes that were already part of the imported project that work just fine.

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

-- modified at 9:11 Monday 16th January, 2006

toxcct16-Jan-06 3:17

16-Jan-06 3:17

and what happens if you change void MyFunction(CString sVal)
with void MyFunction(CString& sVal) ??

TOXCCT >>> GEII power
[toxcct][VisualCalc 2.20][VisualCalc 3.0]

kakan16-Jan-06 3:25

kakan

16-Jan-06 3:25

A long shot...
Have you tried a "Rebuild All"?

#realJSOP16-Jan-06 10:52

16-Jan-06 10:52

Yeah...

I can't understand why the code doesn't work.

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

Nish Nishant16-Jan-06 3:50

Nish Nishant

16-Jan-06 3:50

John

I presume that's a Unicode build. I've found weird behavior when I use ANSI strings with a CString in Unicode builds. Try making that an Unicode string, so the proper constructor gets called. Non-Unicode string constructors are conditionally marked as explicit when it's a Unicdoe build. It's a breaking change that is undocumented.

Regards,
Nish

My blog : Nish’s thoughts on MFC, C++/CLI and .NET

#realJSOP16-Jan-06 11:01

16-Jan-06 11:01

Where do I find out if it's a unicode build? Actually, I think non-unicode would make my life easier...

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

Move / Refresh Windows Taskbar

Nish Nishant16-Jan-06 11:47

Nish Nishant

16-Jan-06 11:47

John Simmons / outlaw programmer wrote:
Where do I find out if it's a unicode build? Actually, I think non-unicode would make my life easier...

Sorry John, the issue with explicit constructors I mentioned does not apply to your case.

And anyway, your code is not a Unicode build, since the CString accepted the non-Unicode string (in a Unicode build you'd have been forced to specify an L"..." or use the _T macro)

Also I tested out the following code on my VC++ 2005 and got the correct results.

void MyFunction(CString sVal)
{
	if (sVal.IsEmpty())
	{
		AfxMessageBox("Empty String");
	}
	else
	{
		AfxMessageBox(sVal);
	}
}

void ThisFunction()
{
	CString myString = "test";
	MyFunction(myString);
}

That code snippet message boxed "test" as expected. So, my best guess is that something happens before the CString gets to MyFunction.

Regards,
Nish

My blog : Nish’s thoughts on MFC, C++/CLI and .NET

u6ik16-Jan-06 1:42

u6ik

16-Jan-06 1:42

I have written some code to change the screen resolution and depth then return them to their original settings. All works fine, but the Windows taskbar moves occasionally to about midscreen. Is there a function which automatically refreshes the taskbar to the bottom of any reresed window? Or a windows function I can use to move the taskbar to the required bottom edge of the visible screen?

Many thanks Wink | ;)

u6ik

-- modified at 7:43 Monday 16th January, 2006

Re: Move / Refresh Windows Taskbar

u6ik16-Jan-06 20:41

u6ik

16-Jan-06 20:41

Well, after a bit of digging I found the answer myself.

SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, NULL, NULL);

You need to notify the shell of a change and force a refresh. No need to move the taskbar around yourself, Windows realises there has been a change and corrects the taskbar positioning.

All good Big Grin | :-D

u6ik

how can i calculate the length of sent data at server side

baldha rakesh16-Jan-06 1:37

baldha rakesh

16-Jan-06 1:37

how can we calculate the length of sent data, from client side ,at server side.
i am sending data from client side but i am not able to know the accurate length of this data at server side.

Thanks N Regards

Bankey Khandelwal
Mobile : 98504-32990
Office : 020 25521888

Solversa Technologies
15, Yeshwant Ghadge Nagar,
Range Hill Road,
Pune - 03,Maharashtra,India.

Re: how can i calculate the length of sent data at server side

Bob Flynn16-Jan-06 2:39

Bob Flynn

16-Jan-06 2:39

If I understand the question properly, you can send a header that contains the length of the packet that is arriving. So when you recieve a packet, you always read a fixed length structure that contain the length of the data arriving, then you can allocate space for the incoming data.

Does that address you question?

Re: how can i calculate the length of sent data at server side

baldha rakesh16-Jan-06 17:15

baldha rakesh

16-Jan-06 17:15

how can send haeder i am sending and receiving as follows

rVal=send(sock, text, strlen(text), 0);

rVal=recv(sock,data,strlen(data),0);

but i am sending text but i can not receive accurate length of text. please send me if you have any example code.
and also a another problem is i have to send to multiple cleint so which method i should apply.please reply me ASAP.
thanks

Re: how can i calculate the length of sent data at server side

Bob Flynn17-Jan-06 3:09

Bob Flynn

17-Jan-06 3:09

Sorry I do not have example code to send - this is something that I did long ago on a DSP processor.

What you can do is send and recieve twice, something like this:

typedef struct{
int packetId; // if this is appropriate for you needs
int len;
}packet_S;

sendHdr.len = strlen(text);
rVal=send(sock,sendHdr,strlen(packet_S),0);
rVal=send(sock,text,sendHdr.len ,0);

rVal=recv(sock,recvHdr,strlen(packet_S),0);
dataLen = recvHdr.len;
rVal=recv(sock,data,dataLen,0);

As far as the best way to send to multiple clients, I do not know. You might do well to post a separate question in the forum again.

I hope this helps.

Text Boxes in C++

Gktony16-Jan-06 0:45

Gktony

16-Jan-06 0:45

Hi all,

I am new to C++ and I want to get the value from a text box merge it with another string and then re-populate the text box. I am using the text box in a windows form.

Here is the code I have tried but doesn't work

string S1;
S1 = this->textBox1->Text;
textBox1->Text = S1 + "Test1";

Thanks

Ben

_AnsHUMAN_ 16-Jan-06 1:01

_AnsHUMAN_

16-Jan-06 1:01

You would be having some control for the text box.
If not go to class wizard and create it. Let us name it as tb.Now you can access the text box text by calling GetWindowText. Modify the string and use SetWindowText to set the text back to the text box

Regards
Anshuman

Owner drawn16-Jan-06 1:10

Owner drawn

16-Jan-06 1:10

For this you have to use SetWindowText() and GetWindowText().

BOOL SetWindowText(          
    HWND hWnd,
    LPCTSTR lpString
);

int GetWindowText(          
    HWND hWnd,
    LPTSTR lpString,
    int nMaxCount
);

TCHAR lpString[100];

GetWindowText(hEdit, lpString, sizeof(lpstring))

_tcscat(lpString, " another string");

SetWindowText(hEdit, lpString)

Now this will work. Smile | :)

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--Never say quits
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toxcct16-Jan-06 1:18

16-Jan-06 1:18

prefer the GetWindowText() and SetWindowText() that handles CStrings :

CString strMsg = <font color=gray>" World"</font>;
CString strEditContent; <font color=green>//let's say "Hello"</font>
 
<font color=green>//gets the edit handle</font>
CEdit* pEdit = (CEdit*)GetDlgItem(IDC_MY_EDIT</font>);
 
<font color=green>//gets the edit string</font>
pEdit->GetWindowText(strEditContent);

 
<font color=green>//concatenate the strings</font>
strEditContent += strMsg;
 
<font color=green>//sets the edit string</font>
pEdit->SetWindowText(strEditContent);

TOXCCT >>> GEII power
[toxcct][VisualCalc 2.20][VisualCalc 3.0]

-- modified at 7:18 Monday 16th January, 2006

Owner drawn16-Jan-06 1:19

Owner drawn

16-Jan-06 1:19

Hmmm, you are right.

But seeing his post I thought he must be using SDK.

Jesus Loves Rose | [Rose]

<marquee direction="up" height="40" scrolldelay="1" step="1" scrollamount="1" style="background:#aabbcc;border-bottom:thin solid 1px #6699cc">
--Owner Drawn Rose | [Rose]

--Nothing special
--Defeat is temporary but surrender is permanent
--Never say quits
--Jesus is Lord Rose | [Rose]

Eytukan16-Jan-06 2:32

Eytukan

16-Jan-06 2:32

Gktony wrote:
string S1;
S1 = this->textBox1->Text;
textBox1->Text = S1 + "Test1";

this is certainly a VB++!! Smile | :)

0x0400:
"But your mind is very complex, very tricky. It makes simple things complicated. -- that's its work. And for centuries it has been trained for only one thing: to make things so complicated that your life becomes impossible."- Osho

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