C / C++ / MFC Discussion Boards

drummer6-Jan-02 12:32

6-Jan-02 12:32

I figured it out. I wasn't doing any cross-thread syncronization, but I added it now using CMutex's and CSingleLock's. Now it works fine. Thanks though.

What would cause strtok to fail?

Stephen Caldwell5-Jan-02 8:23

Stephen Caldwell

5-Jan-02 8:23

In my Non-MFC application i need to use strtok, now i used it in another function and it works fine, but in one function it fails and I don't know why.
Here is the code from the function that works:

int fsConsole::ParseCommandLine(char* line)
{
	//Get the first command
	char* funcname;
	char* values;

	funcname = strtok(line," ");
	values = strtok(NULL, "\n");
	return Execute(funcname, values);
}

Now here is the broken function:

int fsConfigManager::CreateSetting(char* settingName, void* value)
{
	//Get the Component
	char* pComponent = strtok(settingName, ":");
	if (pComponent == NULL)
		return EFS_INVALID;

	char* pSetting = strtok(NULL, "\n");
	if (pSetting == NULL)
		return EFS_INVALID;

	ConfigList.insert(pair<char*, fsItem>(pComponent, fsItem(settingName, (char*)value)));

	return EFS_OK;
}

When strtok is called in the second function i get an access violation.
Thanks in advance.

Stephen Caldwell
Blackfission, CEO
http://blackfission.myip.org:81

Re: What would cause strtok to fail?

Ravi Bhavnani5-Jan-02 8:36

Ravi Bhavnani

5-Jan-02 8:36

strtok() modifies its argument (by inserting '\0's to separate tokens). In the broken function, settingName has been modified and is being passed to fsItem(), which likely expects it to be unmodified.

In general, you should use strtok() with a copy of your original string.

/ravi

"There is always one more bug..."
http://www.ravib.com
ravib@ravib.com

Re: What would cause strtok to fail?

Stephen Caldwell5-Jan-02 8:47

Stephen Caldwell

5-Jan-02 8:47

Thank you. It worked.

Stephen Caldwell
Blackfission, CEO
http://blackfission.myip.org:81

Proper MSComm usage?

5-Jan-02 6:51

I'm relativly new to MFC and would like to write some test code using the MSComm control. I've added one to my dialog and attached a variable to it. I just cannot seem to get the SetOutput() to actually output any bytes. Also, I ran across some "supposidly" working MFC code, but it will not work for me. Could someone please provide a simple example of sending a byte, say 0x90? Here is the "non-working" code that I found:

m_objMSComm.SetRThreshold(1);
m_objMSComm.SetRTSEnable(TRUE);
m_objMSComm.SetSettings("9600,n,8,1");
m_objMSComm.SetSThreshold(1);
m_objMSComm.SetPortOpen(TRUE);

COleSafeArray objOutputBuffer;

int iLoopVar=0;
long iArraySizeInc=0;

BYTE bOutput;

// First Byte to be send

bOutput='A';

objOutputBuffer.PutElement(&iArraySizeInc,(void *) &bOutput);
objOutputBuffer.ResizeOneDim(iArraySizeInc+2);
iArraySizeInc++;

// Secondt Byte to be send

bOutput='B';

objOutputBuffer.PutElement(&iArraySizeInc,(void *) &bOutput);
objOutputBuffer.ResizeOneDim(iArraySizeInc+2);
iArraySizeInc++;

// Third Byte to be send

bOutput='C';
objOutputBuffer.PutElement(&iArraySizeInc,(void *) &bOutput);
objOutputBuffer.ResizeOneDim(iArraySizeInc+2);
iArraySizeInc++;

//sending "ABC" through comm port #1

m_objMSComm.SetOutput((VARIANT)objOutputBuffer);

Thanks in advance!

Fine a file

Jon Newman5-Jan-02 6:30

Jon Newman

5-Jan-02 6:30

I'm trying to write a program that will , on starting, look for a file in the root directory of the CD drive. Of course we all have different CD drive letters so how can i get the software to find the required file?

.NET or not .NET? MFC is the question......

Re: Fine a file

Michael Dunn5-Jan-02 6:49

Michael Dunn

5-Jan-02 6:49

GetLogicalDriveStrings() will return a list of all drive letters on the system. Pass each one to GetDriveType() until you find a CD drive.

--Mike--
My really out-of-date homepage
Buffy's on. Gotta go, bye!
Sonork - 100.10414 AcidHelm
Big fan of Alyson Hannigan.

Removing *Unchanged* Output File (ofstream) :: C++

valikac5-Jan-02 6:00

valikac

5-Jan-02 6:00

Hi.
I am working on an interesting and simple problem. A program I am working on initializes an ofstream object. It does calculations (arbitrary) and writes to the output file. The problem is sometimes it writes new data and sometimes it does not. I am currently using a bool to make sure if it does not write new data, then it should remove the output file when it finishes. There is one false assumption. I am assuming the output file is always empty. That is not true because the output file is openned with "ios::app," which is appending mode. The program sometimes remove files that are not empty.

I tried using the empty() function, but it does not work for an ofstream object. I would like to know the best way to check to make sure an ofstream object is *empty* return from the a end of class or before the program closes.

Thanks,
Kuphryn

Re: Removing *Unchanged* Output File (ofstream) :: C++

Daniel Turini6-Jan-02 22:58

Daniel Turini

6-Jan-02 22:58

Have you tried not opening the file until you write to it ?

Crivo
Automated Credit Assessment

Re: Removing *Unchanged* Output File (ofstream) :: C++

valikac7-Jan-02 8:28

valikac

7-Jan-02 8:28

Thanks.

You made a good point. The way I designed program have it open the output file first. I feel it is more elegant relative to the *user* if I leave the program in its current structure.

I implemented the seekp() and tellg() functions determine whether the program made any changes to the output file.

Kuphryn

extern?

Stan the man5-Jan-02 3:56

Stan the man

5-Jan-02 3:56

Hi.

I have a series of

char* XX[2] = {"Hi", "Hi there"};
....

These are meant to hold txt so that I can change them as a SET by changing the index.

I have a header file to hold these. My question is that I include this file in all my other classes and such that it can use this. Do I have to use extern on all these declarations in those files or another header file? I would only want to change the text in one place and not have this file and another one identical to this except with extern in front of everything. Is this right? I am not too familiar with externs but is this the only way?

If I am not correct, can someone correct me on how to use an index or some way to choose the text but to set it globally I guess so that I can use it in ANY FILE.

Thanks in advance.

Re: extern?

C^hris L^osinger5-Jan-02 4:14

C^hris L^osinger

5-Jan-02 4:14

extern tells the compiler "this is what the variable looks like".

use it like this:

code.h
------
extern int myInt; // this just tells other code that "myInt" is an int, not where it lives (ie. it's address)

code1.cpp
------
int myInt; // this allocates the variable

code2.cpp
------
#include "code.h"

myInt = 5; // use it

-c

Smaller Animals Software, Inc.

Re: extern?

Stan the man5-Jan-02 4:19

Stan the man

5-Jan-02 4:19

For

char* Text[2] = {"hi","hi there"};

THe extern statement would be

extern char* Text[2];

Is this correct?

Re: extern?

C^hris L^osinger5-Jan-02 4:24

C^hris L^osinger

5-Jan-02 4:24

yep, that should do it.

-c

Smaller Animals Software, Inc.

Re: extern?

Rick York5-Jan-02 6:48

Rick York

5-Jan-02 6:48

I like to keep these kinds of things all in one file. Here is a couple of macros that help with doing this.

// in YourHeader.h

#ifdef MAIN
#define Global
#else
#define Global extern
#endif

// if not initializing

Global char *XX[2];

// if you are going to initialize it do this :

#ifdef MAIN

char *YY[2] = { "String 1", "String 2" };

#else

extern char *YY[2];

#endif

// in your source code files
// do this one and only one time

#define MAIN
#include "YourHeader.h"

// no other source files may contain the MAIN definition

Re: extern?

Christian Graus5-Jan-02 9:32

Christian Graus

5-Jan-02 9:32

Somewhat of an aside, but globals are of the devil, if you must use them, you should put them into a namespace.

Christian

I have come to clean zee pooollll. - Michael Martin Dec 30, 2001

Sonork ID 100.10002:MeanManOzI live in Bob's HungOut now

Re: extern?

Tim Smith5-Jan-02 11:01

Tim Smith

5-Jan-02 11:01

Ewww, I bet you think gotos are the spawn of Satan. Smile | :)

Tim Smith
Descartes Systems Sciences, Inc.

Re: extern?

Christian Graus5-Jan-02 11:08

Christian Graus

5-Jan-02 11:08

But of course.

NumberOfTimesIHaveUsedGotoInC = 0;

Christian

I have come to clean zee pooollll. - Michael Martin Dec 30, 2001

Sonork ID 100.10002:MeanManOzI live in Bob's HungOut now

Re: extern?

David Chamberlain7-Jan-02 7:56

David Chamberlain

7-Jan-02 7:56

As a very "general" rule, you should try to avoid declaring variables in a header file, simply because every source file that includes them will re-create that variable's declaration. If you really want a global variable, you should declare it in a source file, and then when another source file needs to access or update it, declare it again in that source file using extern. Extern says "There is a variable (with memory allocated) somewhere else in the program and it looks like this." Separating your global variables like this helps to keep track of them, because you declare them in the source file where they are "owned," and then use extern for everywhere else where they are "used."

While various macros have been developed for use in header files to optionally compile or not compile the extern for variables, this is really just a confusing trick to get the compiler to do what I have described. It's only confusing to you and other programmers, because you still have to find when the original file is to find if the macro #define is made in order to get the original variable declaration.

Dave

"You can say that again." -- Department of Redundancy Department

Tabbed multiple views

Nnamdi Onyeyiri5-Jan-02 3:26

Nnamdi Onyeyiri

5-Jan-02 3:26

I am trying to write a program that has an SDI interface, but has three tabs within that. Does anyone know where i can get the code for this, i have checked out the samples on this site and www.codeguru.com, but none of them use a tabbed interface.

==================================================
When Your Mind Wonders...Where Does It Go???

How to write a service by VC

Vistac5-Jan-02 3:10

Vistac

5-Jan-02 3:10

Hello,
How to write a WinNT service by VC, I read MSDN, it seems use ATL,
but I can't understand clearly, have some kindly give me an example ??
please email to vistac@ms10.hinet.net
Thanks.....
Vistac Wu

Re: How to write a service by VC

C^hris L^osinger5-Jan-02 3:25

C^hris L^osinger

5-Jan-02 3:25

did you try looking on this site first? there are many articles on services here. http://www.codeproject.com/system/

-c

Smaller Animals Software, Inc.

Doc/View Application

5-Jan-02 2:59

Hi All,
I’m doing some processing in method of view(CView) and wanted to display result in my document(CDocument). Its my first application for Doc/View Architecture. I’ve created MFC SDI Application from Project Wizard of VC++ 6.0.
Please guide me for that. Also I’d like to mention that all my document would be ASCII text ya, kind of notepad application but the content would have to be displayed from background process in code of View. I’d like if someone give me direction for implementing Copy data area from that view. No need to cut and paste.
Does this SDI provide me scrolling also when the area will exceed? IS there any change need to be done to introduce scrolling?

Thanks a lot for lot of answers Smile | :)

-- Sumit

Please make a CC of reply at sumit@elitecore.com

Re: Doc/View Application

Eugene Pustovoyt5-Jan-02 4:21

Eugene Pustovoyt

5-Jan-02 4:21

Hi,

You must use the method CView::GetDocument(), that get pointer to the CDocument.

Best regards,
Eugene Pustovoyt
Big Grin | :-D

Sonork ID 100.10002:Yaumen

Re: Doc/View Application

5-Jan-02 5:13

Hey Eugene,
Thanks for your answer, But I'm not aware of how to flow. What methods are used for display? Can you provide me a summery of doing this?
Say I have some thread running on my CView::OnNew(). Now this thread returns some result. And I wanted to Display this text output, in multiple lines. I wanted to provide support to copy that text also.
Thanks for all help and appritiate lot to smart piece of code for steps and overview.

-- Sumit

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