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Le@rner wrote: i want to use memo filed in my access database to store more than 255 char.
By default, a Memo field can store up to 2GB of data, so 255 characters is not a problem.
Le@rner wrote: please tell me how can i use memo filed in access database and CRecordSet?
Much like you would any of the other field types. What specific issue(s) are you having?
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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In access table i m using a Field with Data Type Memo.
in CRecordSet derived class of this table,memo field is RFX_Text type and its variable is of CStringW type.
Than in my application i want to store more than 255 char in this field but some error or exception generate here.
error is "mfc internal error: unable to load error string from resource" and generate CDBException at memory location 0x0885fb9c..
please help me for this.
modified on Wednesday, November 10, 2010 12:13 AM
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Using the debugger, set a breakpoint on the call to Update(), and then step into the internal MFC code until you find where LoadString() is being called.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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hi
i created a new project, a dialog based MFC application.
i inserted a button in the dialog with id IDC_BUTTON1.
i added a member variable of type AcButton derived from CButton to the dialog object to handle WM_LBUTTONDOWN on the button.
1. why is the button enabled while there's no handler for the IDC_BUTTON1 command and i've not included ON_COMMAND_UPDATE_UI in the message map of the dialog? in another words, why the button is enabled by default?!
in this case, i see that the AcButton::OnLButtonDown is called.
in the resource editor, i disable the button. in such a case, the AcButton::OnLButtonDown is not called anymore by clicking on the button. instead, the WM_LBUTTONDOWN is received by the dialog (the parent of the button).
2. who decides to do this?!
3. how can i make mouse events be received by a control in a dialog which cannot be focused nor get enabled? let's say eg. a static text, how can get the mouse events?
i hope i could clarify my three questions. plz answer my by numbers.
thx
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What does the 890818 stand for? *curious*
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this kind of tag is helpful in the following ways for me:
1. i may find my own posts between a plenty of posts without requirement to read them one by one.
2. today is the 18th of the 8th month of the year of 1389. we totally use a different calendar which is the most accurate one in the world, instead of Gregorian. this helps me find when i had posted the question.
3. this makes ppl like u ask the question as a reply to my post. then i get happy to have an answer to my question, for a short moment of the time.  lol
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From Ole Server Application do we have to call this (WM_QUERYENDSESSION)
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Member 2883067 wrote: From Ole Server Application do we have to call this (WM_QUERYENDSESSION)
What you precisely mean with this sentence? The WM_QUERYENDSESSION message is sent by Windows in the initial steps of a shutdown.
If you want to shutdown the operating system (turn-off, reboot, ...) you should use the ExitWindowsEx Function (Windows)[^], that logs off the interactive user, shuts down the system, or shuts down and restarts the system. It sends the WM_QUERYENDSESSION message to all applications to determine if they can be terminated.
For an example on how to use that API, see How to Shut Down the System (Windows)[^]
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I am working on a database application, developed in 'C' programming language, which talks to database through the odbc drivers. What is the best way to track/troubleshoot the 'crash' errors like NULL pointers, memory crashes, etc? As the application is a huge code base, I am looking for one smart way to track the application crashes. Please suggest, if any?
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If you are not already using it, then the best first step is to use your debugger. You cannot do any advanced debugging without a debugger.
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coder21k wrote: What is the best way to track/troubleshoot the 'crash' errors like NULL pointers, memory crashes, etc? As the application is a huge code base, I am looking for one smart way to track the application crashes.
Write a crash report to identify application version, environment, registers, calling stack etc. Then assign each maintainer time to investigate and fix crashes, for a huge code base you probably have multiple teams/maintainers. If you have a ticket systems for defects the teams can create individual bug tickets after investigation and narrowing down the cause of a crash, marked as important. Application crashes are not only annoying for end users, they should be handled with high priority because they could be a sign for quality/security/development weaknesses. As an alternative you could add stress and penetration tests to your test strategy.
Hope it helps 
/M
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hi,
i'm working on a project that capture real time temperature.I managed to capture the real time temperature but when i tried to send the captured values to another device it displayed weird characters eg' ?.After which i did some research again on the codings.I found out that the software i'm using doesn't support %f and i'm required to do some conversion to it.I came up with the codes but its unable to work.Please advice.
my original codes:
void loop(){
float tmpVALUE=0; char dataToSend[100];
if(!BT.createConnection("0003190D102D","02"))
{
USB.println("");
USB.print("--- CONNECTION -- MTU: ");
USB.print(BT.connection_mtu[0],BYTE);
USB.print(BT.connection_mtu[1],BYTE);
USB.println(BT.connection_mtu[2],BYTE);
}
else USB.println("Connection failed");
tmpVALUE = SensorEvent.readValue(SENS_SOCKET5);
if(tmpVALUE>0.5)
{
tmpVALUE=((tmpVALUE-0.5)/0.01);
}
else
{
tmpVALUE=tmpVALUE/0.01;
}
delay(100);
XBee.print("Temperature: ");
XBee.println(tmpVALUE);
delay(5000);
sprintf(dataToSend,"%f",tmpVALUE);
if(!BT.sendData(dataToSend)) USB.println("Data sent OK");
else USB.println("Error while sending data");
modifed
void loop()
{
float testVal=7.3812849; char dataToSend[100];
char converttmpVALUE[100];
if(!BT.createConnection("0003190D102D","02"))
{
USB.println("");
USB.print("--- CONNECTION -- MTU: ");
USB.print(BT.connection_mtu[0],BYTE);
USB.print(BT.connection_mtu[1],BYTE);
USB.println(BT.connection_mtu[2],BYTE);
}
else USB.println("Connection failed");
tmpVALUE = SensorEvent.readValue(SENS_SOCKET5);
if(tmpVALUE>0.5)
{
tmpVALUE=((tmpVALUE-0.500)/0.010);
}
else
{
tmpVALUE=tmpVALUE/0.010;
}
delay(100);
XBee.print("Temperature: ");
XBee.println(tmpVALUE);
delay(5000);
sprintf(dataToSend,"%s",ftoa(converttmpVALUE,testVal,4));
char *ftoa(char *a, double f, int precision)
{
long p[] = {0,10,100,1000,10000,100000,1000000,10000000,100000000};
char *ret = a;
long heiltal = (long)f;
itoa(heiltal, a, 10);
while (*a != '\0') a++;
*a++ = '.';
long decimal = abs((long)((f - heiltal) * p[precision]));
itoa(decimal, a, 10);
return ret;
}
if(!BT.sendData(dataToSend)) USB.println("Data sent OK");
else USB.println("Error while sending data");
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Check what kind of character encoding is supported by the target device.
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[Warning]
Bound-checkings (and any other check) are left to the reader...
[/Warning]
void ftoa(char *buf, float f, int p)
{
int i, n;
unsigned long l
for (n=0; n<p; n++)
f *= 10;
l = (long) (f + .5);
for (n=0; l>0; n++, l/=10)
{
if (n==p)
{
buf[n]='.';
n++;
}
buf[n]= (l % 10) + '0';
}
for(i=0; i<n/2;i++)
{
char c;
c = buf[i];
buf[i] = buf[n-1-i];
buf[n-1-i]= c;
}
buf[n]='\0';
}
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]
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thanks for replying.The solution you gave me doesn't work as my editor gave me an error:(In function 'void loop()':
error: expected primary-expression before 'char').Maybe you would like to take a look at the whole code as I've been trying several methods but it still doesn't work.I'm just a beginner in c++ so do bear with me.Thanks
float tmpVALUE=0;
int n=0;
void setup(){
SensorEvent.setBoardMode(SENS_ON);
XBee.setMode(XBEE_ON);
delay(50);
USB.begin();
USB.println("USB port started...");
USB.close();
BT.ON();
if( BT.flag & BT_ERROR_ON ) USB.println("Error, 'ROK' not received");
else USB.println("BT module ready...");
if(!BT.init()) USB.println("Init OK");
}
void loop()
{
float tmpVALUE=0; char dataToSend[100];
char converttmpVALUE=0;
if(!BT.createConnection("0003190D102D","02"))
{
USB.println("");
USB.print("--- CONNECTION -- MTU: ");
USB.print(BT.connection_mtu[0],BYTE);
USB.print(BT.connection_mtu[1],BYTE);
USB.println(BT.connection_mtu[2],BYTE);
}
else USB.println("Connection failed");
tmpVALUE = SensorEvent.readValue(SENS_SOCKET5);
if(tmpVALUE>0.5)
{
tmpVALUE=((tmpVALUE-0.5)/0.01);
}
else
{
tmpVALUE=tmpVALUE/0.01;
}
delay(100);
XBee.print("Temperature: ");
XBee.println(tmpVALUE);
delay(5000);
sprintf(dataToSend,"%s",converttmpVALUE);
ftoa(char* buf,float f,int p);
{
int i, n;
unsigned long l
for (n=0; n<p; n++)
f *= 10;
l = (long) (f + .5);
for (n=0; l>0; n++, l/=10)
{
if (n==p)
{
buf[n]='.';
n++;
}
buf[n]= (l % 10) + '0';
}
for(i=0; i<n/2;i++)
{
char c;
c = buf[i];
buf[i] = buf[n-1-i];
buf[n-1-i]= c;
}
buf[n]='\0';
}
if(!BT.sendData(dataToSend)) USB.println("Data sent OK");
else USB.println("Error while sending data");
if(!BT.removeConnection()) USB.println("Connection removed");
else USB.println("Error while removing connection");
if(!BT.removeTrustedDevice("0003190D102D")) USB.println("Trusted Device removed");
else USB.println("Error while removing trusted device");
delay(5000);
}
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Hello people!
I have the following (simplified) code:
OVERLAPPED Overlap = {0};
Overlap.hEvent = event_reader_with_CreateEvent;
if (ReadFile(handle_for_com_port, pBuffer, buffer_size, &bytes_read, &Overlap)) ...data read, go on happily...
else if (GetLastError() == ERROR_IO_PENDING)
{
if (WaitForMultipleObjects(1, &Overlap.hEvent, FALSE, dwTimeOut) == WAIT_OBJECT_0)
{
if (GetOverlappedResult(handle_for_com_port, &Overlap, &bytes_read, FALSE)) ...data read, go on happily ...
else if (GetLastError() == ERROR_IO_INCOMPLETE)
{
What to do here???
} else ...IO error, report and go on not so happily...
}
}
So what to do in case of ERROR_IO_INCOMPLETE? Googling around i found code sniplts where they simply try GetOverlappedResult again and again for a while until it succeeds OR some timeout or somesuch occurs. However, time to time i run into the following confusing situation:
1. ReadFile called resulting in ERROR_IO_PENDING
2. Waiting on the event returns with WAIT_OBJECT_0, the event is signalled
3. GetOverlappedResult returns FALSE and the last error code is ERROR_IO_INCOMPLETE, however, if i check the buffer (pBuffer) with the debugger i see that the data is already fully in it, however, bytes_read is 0 and it remains zero and repeatedly calling GetOverlappedResult will always result in ERROR_IO_INCOMPLETE for all ethernity (or at least as long as i was willing to wait).
Anyone knows why this is happening and what i can do to solve it? Another thing that turned up is that if i try to "timeout" from this, i mean, call GetOverlappedResult a few times giving up after a while and continuing will result in "damaged memory block", maybe because the buffer pointed at pBuffer goes out of scope but someone, somewhere still tries to write into it (just a guess)? Anyways, timeouting still can't be a solution because i lose the data that was actually read into the buffer, confusing confusing confusing...help!!!
p.s: if i call GetOverlappedResult with TRUE as the last parameter than it just seem to hang...
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world.
Fry: But this is HDTV. It's got better resolution than the real world <
modified on Monday, November 8, 2010 3:13 PM
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Thank you for the link but i did set up the port using the DCB structure, SetCommState and SetCommTimeouts.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world.
Fry: But this is HDTV. It's got better resolution than the real world <
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That's strange.
Could you try giving TRUE for the third parameter of WaitForMultipleObjects or use WaitForSingleObject!!!
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In the actual code there are more then one event i am waiting for that is why you see WaitForMultipleObjects, i just simplified the code for simplicity. And yes, i am sure that the event signalling the overlapped operation completion is fired, it is the very first event handle inside the array passed to the wait function and i get WAIT_OBJECT_0 from it. Most of the time this seems to be working ok but time to time...
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world.
Fry: But this is HDTV. It's got better resolution than the real world <
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Oh... I've so forgotten the usage of character arrays!
for example:
char * Func (char * sT)
{
char sRet [MAX_STR_SIZE] = "";
strcpy (sRet, sT);
return sRet;
}
And when compiling I get a warning returning address of local variable or temporary
I think I know why it tells me this, but not completely sure... Would it be more reasonable to do void Func (char * sT, char * sRet) ?
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You should really stop home cooked memory handling and write std::string sRet(sT), or (MFC) CString sRet(sT), or ATL::CString sRet(sT) ... other string classes omitted.
cheers,
AR
When the wise (person) points at the moon the fool looks at the finger (Chinese proverb)
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Err... well, I know that and agree with you, but my boss does not think the same. I have mentioned him several times that it is more secure to use std::string or any other, but apparently it is best to use char * and home cooked functions for the system the application will run in.
I understand your worries, I will make sure someone checks my code before it goes on the system.
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piul wrote: my boss does not think the same. I have mentioned him several times that it is more secure to use std::string or any other, but apparently it is best to use char * and home cooked functions for the system the application will run in.
I sympathize  Try find another job or another boss
Meanwhile: piul wrote:
char * Func (char * sT)
{
char sRet [MAX_STR_SIZE] = "";
strcpy (sRet, sT);
return sRet;
}And when compiling I get a warning returning address of local variable or temporary
Your nice compiler warns you that sRet points to deallocated memory when returned.
A solution is to make sRet static: static char sRet [MAX_STR_SIZE] = {0};.
It will be overwritten on each call but valid on return.
For safety use strncpy(sRet, sT, MAX_STR_SIZE - 1).
cheers,
AR
When the wise (person) points at the moon the fool looks at the finger (Chinese proverb)
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You have a buffer that is local - it exists on the stack.
When you exit the routine the stack, for that routine, will no longer exist.
As for the best way to do it it depends on what you are doing. But at a minimum the calling routine would need to pass its local buffer for the copy operation. Or manage it on the heap and make sure to delete it when done.
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