|
I would like to have access to all the pins on a serial port.
If i can get a handle to a COM port using CreateFile, does the interface allow me individual control over the 9 pins? So in other words the 9 signals some of which are DSR, RTS and DTR, can i toggle those through some class?
Thanks,
|
|
|
|
|
LCI wrote: I would like to have access to all the pins on a serial port
This is not possible given that you don't have a driver that supports it.
The standard windows driver for serial devices does not support it.
What do you really mean by "access to all pins"? Do you really need access to all of them, or is it just a few?
Some of the pins are possible to control such as DTR and RTS by the use of ::SetCommState() and the DCB struct.
Do you intend to send serial data at all or do you wish to use the serial port in a way that it's not primarily designed for?
--
Roger
It's supposed to be hard, otherwise anybody could do it!
|
|
|
|
|
I just need to be able to control the RTS, DSR and DTR bits
|
|
|
|
|
The RTS and DTR signals can be controlled manually by using ::SetCommState()[^]and DCB struct[^].
The DSR signal is an hardware monitored input signal that is used for flow control and if found inactive, the data transmission will be suspended. Hence you can neither monitor nor change its state, only inform the hardware that it should be used for flow control or not.
Hope this helps
--
Roger
It's supposed to be hard, otherwise anybody could do it!
|
|
|
|
|
Great thanks... i just have one question on the flow here.
I can use CreateFile to obtain a handle to the port.
Then i can call SetCommState with the handle.. however, the other parameter is a DCB pointer which i will popluate the DSR, RTS and DTR settings how i need to..
Is there anything else i would need to do...
See i am trying to listen on the DSR for a signal to trigger off of that signal,
Then i would like to send signals on RTS and DTR
|
|
|
|
|
LCI wrote: i am trying to listen on the DSR for a signal
I suggest you set up the DCB struct for the port to make use of the DSR signal, i.e. the port suspends data transfer until the DSR line assumes active state.
Use ::WaitCommEvent() to wait for a change on the DSR line and call ::ClearCommError() to verify the state of the DSR line.
Afterwards you can use ::SetCommState() to manipulate the RTS and DTR lines.
Hope this helps
--
Roger
It's supposed to be hard, otherwise anybody could do it!
|
|
|
|
|
|
I launch a cDialog class window from my other CDilaog class.When it is closed by the user I want the parent to set its pointer to zero. How do I do this?
Also do I need to delete the pointer since I am creating with a'new' in the parent?
thanks,
sb
|
|
|
|
|
ns wrote: How do I do this?
You do it in the OnDestroy() function overriding WM_DESTROY from the CDialog class, setting the pointer to 0 with
GetParent()->m_pOnDialog = NULL;
ns wrote: Also do I need to delete the pointer since I am creating with a'new' in the parent?
You can do a
delete this; directly in the OnDestroy() function of the CDialog (which will kill itself, no need to hankde it in the parent window).
~RaGE();
|
|
|
|
|
ns wrote: I launch a cDialog...
Is it a modal or modeless dialog?
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
|
|
Ok, so then why are you wanting/needing to assign NULL to the dialog pointer?
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
|
I have code like
if(!m_tgtInfo)
{
m_tgtInfo = new CTargetInfo(this);
if(!m_tgtInfo) return CDialog::OnCommand(wp, lp);
m_tgtInfo->Create(IDD_DLGTGTINFO, (CWnd*)this);
m_tgtInfo->ShowWindow(SW_SHOW);
}
so if someone does away with the m_tgtInfo window then the next time I enter this function, I want to pop up a new CTargetInfo window. If m_tgtInfo is not set to null by somebody I'll never enter the block to create a new window.
Hope this makes sense.
APpreciate your input!
sb
|
|
|
|
|
In the modeless dialog's PostNcDestroy() method, right before deleting the this pointer, send the parent a UDM indicating that the dialog is just about to be destroyed. In the parent's handler for the UDM, assign NULL to m_tgtInfo.
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
|
|
Hi,
I am having this run time error message.
Run-Time Check Failure #2 - Stack around the variable 'buffer' was corrupted.
It makes sense for me, but
Anybody could give me some detail ideas about this error message?
Thanks!
Yonggoo
|
|
|
|
|
Yonggoo wrote: It makes sense for me, but
Anybody could give me some detail ideas about this error message?
If it makes sense for you, what further explanation do you require?
See here for possibilities.
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
|
See where?
I am not the person that asked this question, but I have done many searches. I find a few questions in other sites and many in this site about this specific error message, but there is nothing that provides a diagnostic solution. In other words, nowhere is there something explaining how to diagnose this problem. It is easy to say to search for answers and I have provided that answer to to others many times before in other forums. Yet in this situation, the answer is not easy to obtain by simply searching. So did you look to see if your answer is any help? I think not. I think you were stuck in the mode of saying to search, but you don't really know the answer and did not look to see if searching has any value for this problem.
|
|
|
|
|
I see "delete this" in a lot of code. For example, in an SDI application, when user clicks on a button on the view, the application needs to swap to a different view. so it will delete the current view and create a new view, "delete this" will be performed somewhere near to the end of the message handler of the button, which is a member function. What is the life time of all member variables at this point? Are they all destructed? Does this mean if I'm trying to acces those variables right after the "delete this", the application might crash?
Thanks!
|
|
|
|
|
You'll also see delete this in the context of modeless dialog boxes.
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
|
You can call delete this from a member function: After doing so you can't access any member variables or call any non-static member functions that do as the memory for the class instance has been returned to the heap from whence it came and the class invariants have no doubt been invalidated by the destructor.
Steve
|
|
|
|
|
Hi All,
I am creating a list box with multiple selection at a time.
I would appreciate if someone let me know how to add items in LIST BOX using MFC.
For example: I need to add USA, CANADA, MEXICO, ENGLAND, INDIA, CHINA in my list.
How to add these itmes?
Do I need to write code or just can do it other way?
Thanks in advance
MFC
|
|
|
|
|
Preeti9 wrote: I would appreciate if someone let me know how to add items in LIST BOX using MFC.
Use CListBox::AddString() or CListBox::InsertString().
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
|
Thanks for your help.
Should it be like this:
[\code]
CListBox::AddString()
{
AddString("USA");
AddString("CANADA");
.....
..
}
C++Prog
|
|
|
|
|
No. You will need a CListBox control variable (use ClassWizard for this), then call AddString() in the context of that variable.
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
"There is no death, only a change of worlds." - Native American Proverb
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif)
