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There is a way, and that is to used a serial interface (maybe with a USB to serial converter if you want) and control the handshake lines. This won't provide many lines, but is cheap and fast with a little bit of level shifting hardware.
Use one of the serial classes in http://www.codeproject.com/system/[^] that can directly control and read these lines.
Elaine ![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
The tigress is here 
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I'm sorry, but "handshake lines"? I'm completely new to this sort of thing...
Thanks!
If you have a problem with my spelling, just remember that's not my fault. I (as well as everyone else who learned to spell after 1976) blame it on Robert A. Kolpek for U.S. Patent 4,136,395.
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The serial ports (COM ports) on your PC have transmit and receive data lines, plus some input and output lines which can be used to control data flow. The standard is RS232.
[^] provides a sample pinout. These signals are driven between +10 and -10 volts and certain ones can be used as individual inputs and outputs with a little electronics. Using a serial class which allows control of individual lines will let you use 2-3 output lines withotu having to write device drivers and is a lot cheaper than buting an I/O card to put inside the PC.
In your case, two output RTS and DTR are available on a standard PCserial port connector. If two ar enough then you're ok. If you need a lot more than two then it might be best to look at adding a digital I/O card to your PC since these usually come with device drivers.
Elaine
The tigress is here
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Thanks for the help! If I only wanted to flash an LED, then I would only need a serial port cable (and my LED) and some lines of code?
Trollslayer wrote:
[^] provides a sample pinout.
Also, was this supposed to have a link in it? Just wondering...
I would only need one output for an LED, right? I guess I would send bogus information through the output line while I wanted to have the light on?
Thanks, I know I'm asking a bunch of questions!
If you have a problem with my spelling, just remember that's not my fault. I (as well as everyone else who learned to spell after 1976) blame it on Robert A. Kolpek for U.S. Patent 4,136,395.
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Yes, one output.
If you use a line such as RTS on pin 7 of the 9 pin serial connector and ground on pin 5 then you can control the RTS pin with a serial port class that allows individual handshake pin control.
This is much better than trying to send data continuously although that would work most of the time.
Elaine
The tigress is here
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I reopened a program to work on and now I receive the message below when I try to compile. I looked at the FAQ section of the forum and found some similar items. I think 2.3 might be what I need but it didn't work. I did find the "msvcrtd.lib" file on my VC++ cd and I copied it into the LIB folders, but it didn't help. I'm stuckaroo.
--------------------Configuration: StdAfx - Win32 Debug--------------------
Compiling...
StdAfx.cpp
Linking...
msvcrtd.lib(crtexe.obj) : error LNK2001: unresolved external symbol _main
Debug/StdAfx.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
StdAfx.exe - 2 error(s), 0 warning(s)
--------------------------------------------------
I tried to do FAQ 2.3. but then got this message below:
--------------------Configuration: StdAfx - Win32 Debug--------------------
Linking...
LINK : fatal error LNK1104: cannot open file "msvcrtd.obj"
Error executing link.exe.
StdAfx.exe - 1 error(s), 0 warning(s)
-----------------------------------------------------
I went to MSDN.com and typed in "fatal errorLNK 1104" and got the following message:
Microsoft JScript runtime error '800a0007'
Out of memory
/search/app/Search_Execute29.asp, line 5476
------------------------------------------------------
I'm sure that's irrelevant
Thanks, Dave
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if it is ATL look for _ATL_MIN_CRT in project setting s and remove it.
Second issue is if you specify msvcrtd in linker settings it is automatically assumes msvcrtd.obj. You have to explicitly specify "msvcrtd.lib"
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I tried FAQ 2.4 in the forum, but I didn't see any of the ATL MIN or CRT items in the preprocessor area of the c\C++ settings. I'm not sure what is wrong.
also, when I type in msvcrtd.lib, I get the following message instead...
Linking...
msvcrtd.lib(crtexe.obj) : error LNK2001: unresolved external symbol _main
Debug/StdAfx.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
StdAfx.exe - 2 error(s), 0 warning(s)
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Is there any stable and reliable XML Reader/Writer classes anywhere that could be used around here? My particular need is for something for VC6 actually.
thank you
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Have you looked at the XML DOM?
http://msdn.microsoft.com/library/en-us/xmlsdk30/htm/xmmscxmlreference.asp?
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I have been using microsoft's DOM as well, but recently I've been thinking of using CodeProject's own PugXML.
http://www.codeproject.com/soap/pugxml.as[^]
Its seems to be a lot faster and lighter than the DOM. Doesn't have all the features of the DOM, but probably don't need them in most everyday projects anyway.
"..Even my comments have bugs!"
Inspired by Toni78
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Hi! How can i get IP addresses in a windows application?
-- Steve
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What do you mean by get? If you mean input, I typically use a plain old regular edit box, but there is an ip address edit box control that you could use. Or do you mean get the IP Address of the current machine? Or get the IP address of machines your connected to?
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Try gethostname() to get host name, then gethostbyname() to get host information
g_elbert
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Another solution is getaddrinfo() and getnameinfo().
Kuphryn
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I am trying to use the SystemTimeToVariantTime(...) function so that I can convert systemTime to
a double.
The MSDN says that I need to include the oleauto.h file and
add the oleaut32.lib file to my project.
when I try to include the oleauto.h file I get the following errors.
d:\program files\microsoft visual studio\vc98\include\oleauto.h(30) : error C2143: syntax error : missing ';' before 'const'
d:\program files\microsoft visual studio\vc98\include\oleauto.h(30) : error C2501: 'EXTERN_C' : missing storage-class or type specifiers
d:\program files\microsoft visual studio\vc98\include\oleauto.h(30) : error C2146: syntax error : missing ';' before identifier 'IID_StdOle'
d:\program files\microsoft visual studio\vc98\include\oleauto.h(30) : error C2734: 'IID' : const object must be initialized if not extern
d:\program files\microsoft visual studio\vc98\include\oleauto.h(30) : fatal error C1004: unexpected end of file found
Any ideas why I get these errors?
thanks,
sj
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what compiler are you using (VC 6, VC7)?
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then I need to see full cpp file compilation of which gives an error
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I have an array of structs and the size is [1] so there are 2 places in the array.
Is there anyway that I can make an array with the size of [0] so there will only be 1 instance in it?
thanks,
sj
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Yes when you create an array of size [1] there is only one place in the array, Array[0].
[EDIT]
In a array of size 1 you may not use Array[1].
[/EDIT]
John
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OK, thanks
sj
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The same is true in the general case an array of size N you can index only N elements 0 .. N-1.
John
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