C / C++ / MFC Discussion Boards

Re: Release crashes but debug works.

Albert Holguin12-Apr-11 7:09

Albert Holguin

12-Apr-11 7:09

>> is not type safe and reading incorrect input type leads to undefined behavior

Re: Release crashes but debug works.

Stefan_Lang12-Apr-11 21:23

Stefan_Lang

12-Apr-11 21:23

Same with bytewise input: you just delay the problem from the reading part to the interpreting part. In either case you have to somehow validate the resulting values. Unfortunately this is almost impossible with binary inputs, and for that reason alone I'd retract my suggestion of using >> here.

Re: Release crashes but debug works.

Albert Holguin11-Apr-11 16:04

Albert Holguin

11-Apr-11 16:04

a couple of other things... this is managed C++, belongs in the C++/CLI forum... what happens if your open file fails? the function will lead to a program crash since you have no error handling... i really hope this is just pseudo-code and not your real thing, if its your real thing, you may want to take a step back to the basics.

Re: Release crashes but debug works.

Cyclone_S15-Apr-11 9:49

Cyclone_S

15-Apr-11 9:49

Its the real thing. Yea I know its bad but it works for what i'm doing. Suggestions on how to improve it are welcome.

Re: Release crashes but debug works.

Stefan_Lang11-Apr-11 22:23

Stefan_Lang

11-Apr-11 22:23

As a rule of thumb, I found that most crashes that only happen in release versions are due to lack of intialization: In debug mode, all variables are initialized with 0 by default. In release mode, this is not the case. Specifically for pointers this can have disastrous consequences, e. g. when you test try to delete an object from a non-null pointer which presumably points to an object created by new.

The best way to avoid these type of errors is to always explicitely initialize a variable on the same line that declares them.

The best way to treat with these errors is locate the part of the code that causes it, and make sure every variable is properly initialized.

Re: Release crashes but debug works.

Cyclone_S15-Apr-11 9:45

Cyclone_S

15-Apr-11 9:45

Well you guys were right about not initializing those variables. That fixed the problem. Thanks.

I'm not sure what's wrong with my code. How would you re-write it. I'm checking for under scores to check for the next score.

The file looks like this:

100_
200_
300_
400_

Re: Release crashes but debug works.

Stefan_Lang26-Apr-11 0:28

Stefan_Lang

26-Apr-11 0:28

Wait, are you saying you're reading a standard ASCII text file? Confused | :confused:

If so, why bother reading it as binary, byte by byte? Just open a normal file stream and use its standard operator >> to stream the numbers into your variables.

Try these functions to write and read your

void WriteScores(const std::vector<int>& scores) {
   int nscores = (int) scores.size();
   std::ofstream scorestream("Myscores.txt");
   scorestream << nscores;            // write number of entries
   for (int i=0; i < nscores; ++i)
      scorestream << ' ' << scores[i]; // write entries, using blank (' ') as separator
}
int ReadScores(std::vector<int>& scores) {
   int nscores = 0;
   std::ifstream scorestream("Myscores.txt");
   scorestream >> nscores;
   scores.resize(nscores);
   for (int i=0; i < nscores; ++i)
      scorestream >> scores[i];
   return nscores;
}

You may want to add in some extra code to check for premature end of file or failure to create/write or read the file. You might also want to check the state of the filestream after reading each number to make sure an actual integer was read (if there was no integer, the resulting value will be 0, but since 0 may be a valid value, you can check on the state of your stream variable instead)

CMFCMenuBar, cleartype? [Solved]

bob1697211-Apr-11 6:00

bob16972

11-Apr-11 6:00

I've noticed that every new porject I create that utilizes the menu class from the MFC Feature Pack appears to utilize cleartype (or some form of font smoothing) regardless of my system settings.

I've looked for some way to disable it but so far have not found anything.
Does anyone know how to manipulate the settings for whether a CMFCMenuBar uses ClearType (or any type of font smoothing in general)?

UPDATE:
This might do the trick (Appears to work so far) and it appears to carry over to status bar, view tabs, etc...

void CMainFrame::DisableClearType(BOOL bDisable)
{
	/*
	This method provides a way to switch clear type font
	quality on or off from the OnApplicationLook method.

	NOTE: The quality flag for PROOF_QUALITY remains set.
	*/

	LOGFONT logFont = {0};

	CFont& font = (CFont&)CMFCMenuBar::GetMenuFont();
	font.GetLogFont(&logFont);

	if (bDisable) {

		// Remove the antialiasing flag
		logFont.lfQuality &= (~ANTIALIASED_QUALITY);

	} else {

		// Set the antialiasing flag
		logFont.lfQuality |= ANTIALIASED_QUALITY;
	}

	CMFCMenuBar::SetMenuFont(&logFont);
}

void CMainFrame::OnApplicationLook(UINT id)
{
	CWaitCursor wait;

	theApp.m_nAppLook = id;

	switch (theApp.m_nAppLook)
	{
	case ID_VIEW_APPLOOK_WIN_2000:
		CMFCVisualManager::SetDefaultManager(RUNTIME_CLASS(CMFCVisualManager));
		DisableClearType(TRUE);
		break;

	case ID_VIEW_APPLOOK_OFF_XP:
		CMFCVisualManager::SetDefaultManager(RUNTIME_CLASS(CMFCVisualManagerOfficeXP));
		DisableClearType(FALSE);
		break;
...

modified on Monday, April 11, 2011 3:53 PM

Re: CMFCMenuBar, cleartype?

Hans Dietrich11-Apr-11 6:23

Hans Dietrich

11-Apr-11 6:23

You can do it for the entire system, but I don't know of any way to do it for just one app. You might check the BCGSoft forums, they might have a secret API.

Best wishes,
Hans

[Hans Dietrich Software]

Re: CMFCMenuBar, cleartype?

bob1697211-Apr-11 7:22

bob16972

11-Apr-11 7:22

Hans Dietrich wrote:
You can do it for the entire system, but I don't know of any way to do it for
just one app

The single MFC Feature Pack application is ignoring my system settings so I thought there might be a way to force it to behave and pay attention to the system settings but so far, I've dug around in the BCGSoft/Microsoft source code for CMFCVisualManager and the label/caption drawing code simply uses the DC passed in so I guess I need to see where that DC comes from and see if it can be modified.

I'll dig around the BCGSoft site. I have to say, by the time I figure out how to use this Feature Pack stuff, they'll have moved on to something new again.

Re: CMFCMenuBar, cleartype?

Hans Dietrich11-Apr-11 13:02

Hans Dietrich

11-Apr-11 13:02

Post a question on the BCGSoft forums.

Best wishes,
Hans

[Hans Dietrich Software]

Re: CMFCMenuBar, cleartype?

bob1697211-Apr-11 10:25

bob16972

11-Apr-11 10:25

Didn't have the secret API but something in the BCGSoft FAQ made a neuron fire.
Thanks for the assistance.

How to implement WebSocket Client in C

Parthi_Appu11-Apr-11 1:48

Parthi_Appu

11-Apr-11 1:48

Hi All,
I have to hit a WebSocket server and have to maintain the connection alive.
Please share some article about implementing a WebSocket Client application in C.

Thanks All.

Do your Duty and Don't expect the Result

Re: How to implement WebSocket Client in C

«_Superman_»11-Apr-11 2:24

«_Superman_»

11-Apr-11 2:24

For a socket client in Windows you basically need to call the following functions in order -
WSAStartup[^] - Initialize winsock.
socket[^] - Create the socket specifying the required protocol like TCP, UDP etc.
connect[^] - Connect the previously created socket to the specified server.

After this step the connection is ready.

To communicate with the server you can use the following functions -
send[^]/sendto[^] - Send a stream of bytes to the server.
recv[^]/recvfrom[^] - Receive a stream of bytes from the server.

To tear down the connection the following functions must be called -
closesocket[^] - Disconnect
WSACleanup[^] - Cleanup winsock.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: How to implement WebSocket Client in C

Parthi_Appu11-Apr-11 20:49

Parthi_Appu

11-Apr-11 20:49

Thanks for the reply.. but i'm not looking for normal Socket implementation. Any way i got little help here http://en.wikipedia.org/wiki/WebSockets[^]

Do your Duty and Don't expect the Result

Re: How to implement WebSocket Client in C

markkuk11-Apr-11 23:26

markkuk

11-Apr-11 23:26

The WebSocket protocol works on top of a normal TCP socket connection, so you must understand Winsock first before you can start implementing WebSockets.

Re: How to implement WebSocket Client in C

Parthi_Appu12-Apr-11 2:58

Parthi_Appu

12-Apr-11 2:58

Thanks for the reponses.. guess i'm not clear with my question..
I'm clear about the WinSocket APIs.. just need to know the WebSocket Handshake details..
I got the below header from Wikipedia & i want to know what are all the things are variable values in this header?

GET /demo HTTP/1.1
Upgrade: WebSocket
Connection: Upgrade
Host: example.com
Origin: http://example.com
Sec-WebSocket-Key1: 4 @1  46546xW%0l 1 5
Sec-WebSocket-Key2: 12998 5 Y3 1  .P00
 
^n:ds[4U

As far as i know the /demo in first line, Host & Origin will change.. but exactly what will be the values?
Will the values of Key1, Key2 & the last 8 byte values also change?

I have to hit the server which has the format as ws://xxx.xxx.xxx.xxx:8181/websock
Also is it possible to send any extra information in the above handshake header? if so what will be its format?

Thanks Again.

Do your Duty and Don't expect the Result

Re: How to implement WebSocket Client in C

Indivara12-May-11 19:03

Indivara

12-May-11 19:03

For anyone who finds this thread -
Article - Web Socket Server[^] and update[^] can be used as references.

Re: How to implement WebSocket Client in C

Manu Dhundi12-Dec-11 8:55

Manu Dhundi

12-Dec-11 8:55

Can websockets be implemented using CURL ?

Also it seems that once the client receives "HTTP/1.1 101 WebSocket Protocol Handshake" it should just wait on recv or recvfrom. Am I correct ? If so, who closes the socket connection once all communication is done? The server or the client ?

Thanks

How can I check if LPCTSTR is empty ?

_Flaviu10-Apr-11 20:57

_Flaviu

10-Apr-11 20:57

If I have an LPCTSTR lpszString , how can I check if lpszString is empty ? Either , if is NULL , is correct lpszString == NULL ?
Thank you .

Re: How can I check if LPCTSTR is empty ?

Hans Dietrich10-Apr-11 21:10

Hans Dietrich

10-Apr-11 21:10

The best way is to make two checks:

if ((lpszString == NULL) || (lpszString[0] == 0))
{
    [lpszString is NULL or empty ]
}

Best wishes,
Hans

[Hans Dietrich Software]

Re: How can I check if LPCTSTR is empty ?

_Flaviu10-Apr-11 21:20

_Flaviu

10-Apr-11 21:20

Thank you , does function .

Re: How can I check if LPCTSTR is empty ?

Rajesh R Subramanian10-Apr-11 21:22

Rajesh R Subramanian

10-Apr-11 21:22

if(!lpszString || !*lpszString){
	//String is either NULL or empty
}

"Real men drive manual transmission" - Rajesh.

Re: How can I check if LPCTSTR is empty ?

Rob Grainger10-Apr-11 23:44

Rob Grainger

10-Apr-11 23:44

In C and C++, strings are null-terminated. As such the last character will always be a NUL character (ASCII 0).

Consequently, any string (char*, const char*, LPTSTR, LPCTSTR etc.) can be checked for empty using:

LPCTSTR sz;
if (!sz[0]) { /* string is empty */ }

However, commonly you also need to check if the string pointer is null - this means that the pointer does not refer to a string at all, rather than that the string is empty:

LPCTSTR sz;
if (!sz) { /* string is null */ }

Commonly, the two must be used together to check for empty or null:

if (!sz || !sz[0]) { /* empty or null */ }

Re: How can I check if LPCTSTR is empty ?

_Flaviu11-Apr-11 5:45

_Flaviu

11-Apr-11 5:45

Thank you all , I learned something here !

modified 2-Jan-19 3:54am.

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