C / C++ / MFC

Re: Question about stdin under multi-process environment.

25-Jul-03 23:55

Hello,

stdin is just a buffer. When you type characters in you console app, they are all put in the buffer.

I recommand that you don't use close(stdin) in a child process that shares the stdin with the parent process! That way, your parent process can't read from stdin and you'll get runtime errors. (if you are able to close stdin in the first place Smile | :)

)

hope this helps a bit...

George226-Jul-03 1:03

George2

26-Jul-03 1:03

Thanks, Bob buddy!

But I am but agree with you. Under Linux environment, even if a parent process close stdin and the child process can still read from stdin.

I can give you an example, the codes are taken from open source project,
miniterm,

--------
switch (fork())
{
case 0: /* child */
/* user input */
close(1); /* stdout not needed */
for (c=getchar(); c!= ENDMINITERM ; c=getchar()) write(fd,&c,1);
tcsetattr(fd,TCSANOW,&oldtio); /* restore old modem setings */
tcsetattr(0,TCSANOW,&oldstdtio); /* restore old tty setings */
close(fd);
exit(0); /* will send a SIGCHLD to the parent */
break;
case -1:
perror("fork");
tcsetattr(fd,TCSANOW,&oldtio);
close(fd);
exit(-1);
default: /* parent */
close(0); /* stdin not needed */
sa.sa_handler = child_handler;
sa.sa_flags = 0;
sigaction(SIGCHLD,&sa,NULL); /* handle dying child */
while (STOP==FALSE) /* modem input handler */
{
read(fd,&c,1); /* modem */
write(1,&c,1); /* stdout */
}
wait(NULL); /* wait for child to die or it will become a zombie */
break;
}
--------

So, what do you think about it?

regards,
George

Re: Question about stdin under multi-process environment.

Bob Stanneveld27-Jul-03 1:09

Re: Question about stdin under multi-process environment.

27-Jul-03 1:09

Hmmm, sorry, can't help you there, I don't have any knowledge about linux/unix/... OS's Blush | :O

George227-Jul-03 1:15

George2

27-Jul-03 1:15

Thanks all the same, Bob buddy!

George

Linking error

eddymohd25-Jul-03 17:58

eddymohd

25-Jul-03 17:58

Why do i get this linking error.. what it realy means.. i read in the MSDN but does not realy understand it..

Linking...
Creating library ../../bin/MyDLL.lib and object ../../bin/MyDLL.exp
LINK : warning LNK4089: all references to "MyDLL1.dll" discarded by /OPT:REF
LINK : warning LNK4089: all references to "MyDLL2.dll" discarded by /OPT:REF

Michael Dunn25-Jul-03 18:20

Michael Dunn

25-Jul-03 18:20

It's a warning, not an error. You are linking with the import LIBs for MyDLL1 and MyDLL2, but you are not calling any functions in either of those DLLs. From the /OPT:REF help:

Use /OPT:REF to eliminate functions and/or data that is never referenced.

Since you never use anything in those DLLs, the linker removes the import LIBs so MyDLL.dll doesn't (needlessly) implicitly link with those other two DLLs.

--Mike--
"Big handwavy generalizations made from a position of deep ignorance is one of the biggest wastes of time on the net today.
-- Joel Spolsky
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber

eddymohd25-Jul-03 19:08

eddymohd

25-Jul-03 19:08

thanks mike.. realy appreciate it..

Bob Stanneveld25-Jul-03 19:32

25-Jul-03 19:32

Hello,

Is there also a #pragma command availeble for that? thanks

A student knows little about a lot.
A professor knows a lot about little.
I know everything about nothing.

Michael Dunn25-Jul-03 20:21

Michael Dunn

25-Jul-03 20:21

For disabling the warning? Probably, but that's the total wrong way to go. When you get a warning, the compiler is flagging something it thinks is wrong. In 99% of the cases, the compiler is right. Fix the warning, don't shut the compiler up.

(The 1% would be for example C4786 in VC 6 which is harmless but unavoidable when using STL.)

--Mike--
"Big handwavy generalizations made from a position of deep ignorance is one of the biggest wastes of time on the net today.
-- Joel Spolsky
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber

Bob Stanneveld25-Jul-03 23:45

25-Jul-03 23:45

Thanks for the advice Big Grin | :-D

... I've got some warnings to fix;)...

A student knows little about a lot.
A professor knows a lot about little.
I know everything about nothing.

Getting Selection from CHTMLEditView

Atlantys26-Jul-03 10:32

Atlantys

26-Jul-03 10:32

Michael Dunn wrote:
The 1% would be for example C4786 in VC 6 which is harmless but unavoidable when using STL

:shudder: C4786 is such an ugly message.

I prefer to wear gloves when using it, but that's merely a matter of personal hygiene
[Roger Wright on VB]

Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning.
[Rich Cook]

Matt Gates25-Jul-03 15:53

Matt Gates

25-Jul-03 15:53

I would like to get at the selection in a CHTMLEditView so I can modify it and reinsert it back in to the view. Specifically I am looking to add the option to format the selection as a superscript or subscript. If I can get what is selected on screen into a CString I will be 90% there. Any suggestions? TIA

Matt (Padawan Learner)

Tom Archer25-Jul-03 16:32

25-Jul-03 16:32

The easiest way would be to copy the selected text to the clipboard and then retrieve the text from the clipboard

// Copy selected text to clipboard using CHtmlEditView base 
// class (CHtmlEditCtrlBase) ExecHelperNN function
ExecHelperNN(IDM_COPY)

I have an article on CP that illustrates how to retrieve text from the clipboard.

Cheers,
Tom Archer
Inside C#,
Extending MFC Applications with the .NET Framework
It's better to listen to others than to speak, because I already know what I'm going to say anyway. - friend of Jörgen Sigvardsson

Matt Gates25-Jul-03 19:53

Matt Gates

25-Jul-03 19:53

Thanks, that should get me going in the right direction. I don't suppose you have a link to that article?

Matt (Padawan Learner)

Tom Archer26-Jul-03 2:33

26-Jul-03 2:33

http://www.codeproject.com/clipboard/archerclipboard1.asp[^]

Cheers,
Tom Archer
Inside C#,
Extending MFC Applications with the .NET Framework
It's better to listen to others than to speak, because I already know what I'm going to say anyway. - friend of Jörgen Sigvardsson

Tom Archer26-Jul-03 2:35

26-Jul-03 2:35

Pasting text basically amounts to the following

if (OpenClipboard())
{
 // Retrieve the Clipboard data (specifying that
 // we want ANSI text (via the CF_TEXT value).
 HANDLE hClipboardData = GetClipboardData(CF_TEXT);

 // Call GlobalLock so that to retrieve a pointer
 // to the data associated with the handle returned
 // from GetClipboardData.
 char *pchData = (char*)GlobalLock(hClipboardData);

 // Set a local CString variable to the data
 // and then update the dialog with the Clipboard data
 CString strFromClipboard = pchData;

 // Unlock the global memory.
 GlobalUnlock(hClipboardData);

 // Finally, when finished I simply close the Clipboard
 // which has the effect of unlocking it so that other
 // applications can examine or modify its contents.
 CloseClipboard();

Cheers,
Tom Archer
Inside C#,
Extending MFC Applications with the .NET Framework
It's better to listen to others than to speak, because I already know what I'm going to say anyway. - friend of Jörgen Sigvardsson

Matt Gates26-Jul-03 15:58

Matt Gates

26-Jul-03 15:58

Thanks a lot, that article did the trick.

Matt (Padawan Learner)

how to make a groupbox's title transparent

Niall Barr26-Jul-03 4:30

Niall Barr

26-Jul-03 4:30

This seems to work...

//Derived from a table insert function that I can't remember the original source of.
CString CHTMLEditView::GetSelection(void)
{
	IDispatch * pDocDisp = NULL;
	IHTMLDocument2* pDoc;
	IHTMLSelectionObject* pSelObj;
	IHTMLTxtRange* pTxtRange;
	CString cstext;
	pDocDisp = GetHtmlDocument();
	HRESULT hr = pDocDisp->QueryInterface( IID_IHTMLDocument2, (void**)&pDoc );
	if (SUCCEEDED(hr)) {
		hr = pDoc->get_selection(&pSelObj);
		CComBSTR p;
		pSelObj->get_type(&p); // Should test this is suitable "Text" or "None"
		if ((SUCCEEDED(hr))&&((p==L"Text")||(p==L"None"))) {
			hr = pSelObj->createRange((IDispatch**)&pTxtRange);
			if (SUCCEEDED(hr)) {
				BSTR text;
				pTxtRange->get_htmlText(&text);
				cstext = text;
				SysFreeString(text);
				pTxtRange->Release();
			}
			pSelObj->Release();
		}
		pDocDisp->Release();
		pDoc->Release();
	}
	return cstext;
}

To put a string back into the selection use pTxtRange->pasteHTML(text) instead of pTxtRange->get_htmlText(&text)

Niall.

allenhu25-Jul-03 15:28

allenhu

25-Jul-03 15:28

i want to make a groupbox's title transparent,can I

Re: how to make a groupbox's title transparent

Tom Archer25-Jul-03 17:15