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Hi,
I wonder if it´s possible to use the function "select" with serial ports. I think under linux it´s possible but under Windows select returns -1 and WSAGetLastError gives me 10038 (Socket operation on nonsocket. An operation was attempted on something that is not a socket. Either the socket handle parameter did not reference a valid socket, or for select, a member of an fd_set was not valid.)
pseudo code:
HANDLE h = CreateFile( COM1 )
...
FD_SET( (int)h, readfds)
select( 0, readfds, NULL, NULL, timeout )
read the data from serial port
I think the problem is the cast of the HANDLE h to int...
Another possibilty would be the function WaitCommMask but I need a timeout-feature. Has anyone an idea if select can be used with serial ports (under Win)?
Thanks in advance!
Sebastian
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Welcome to code project! ![Beer | [beer]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/beer.gif)
A little advice for posting here in the forums. It might not be a good idea to ask if something is possible and then follow that up with a system error message that clearly states it is not possible. People here deal with some really dense posters most days and you don't really want to make yourself seem like one of those if you really want some help.
sevenH wrote: I need a timeout-feature.
Can you be more specific? Timeout for what?
What is your background dealing with asynchronous operations? There are many different solutions to choose from when working in this area, however none of them should be entered into casually. If you lack experience in these areas you need to take some time to study the subject. There is no magic function to use that makes everything work as intended during asynchronous operations.
led mike
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sevenH wrote: I need a timeout-feature
Does SetCommTimeouts give you what you need?
Judy
Be wary of strong drink. It can make you shoot at tax collectors - and miss.
Lazarus Long, "Time Enough For Love" by Robert A. Heinlein
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Hi All,
i was talking to a guy .. who asked about return 0 or return 1
i told him that it return 0 means code have no run time error and if its return 1 it has some error ...
he asked me from where its coming .. i told its coming from comipler ...
but my answer was not as per his expectation can you please more clerify what should i answer in such cases..
vikas da
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I think the return value always comes from your code.
I think the compiler only compiles the code and gives you the .obj file and does not return any value.
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lets see a simple code
int main ()
{
return 0;
}
in above return 0 is defintly user defined .. is there no relation of this return 0 with compiler ...
i am not very sure .. 
vikas da
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Well, in C/C++, 0 means false and non-zero means true. For instance, in platform SDK,
#define FALSE 0
#define TRUE 1
But that is not the same with application exit codes. If the application exit code is 0, then its treated as executed successfully, or else its a warning or error. Check this link[^].
In summery, don't confuse with zero in C/C++ and that of standard DOS exit codes. Both have different meaning. 
Regards,
Jijo.
_____________________________________________________
http://weseetips.com[ ^] Visual C++ tips and tricks. Updated daily.
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Thanks Jijo...
so while executing an application or better to say a programm where these DOS Exit codes comes in picture....
1.During comilation..?
2.During run time..?
and how they are handeled..
Thanks again...
vikas da
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Ofcourse during runtime. Dos execute code comes to scene while executing the applications. Seems you need more explanation.
Dos exit code is the return code that every dos application [as well as windows applications] should return. And as per standard, 0 means its executed successfully. The exit code of last executed application is stored in environment variable - ERRORLEVEL. For instance, take the command prompt and type these two commands.
copy blabla balalala
echo %errorlevel%
Since the copy command failed, you can see return code as 1. if you execute a successful command it should return 0.
For C/C++ compiled application, exit code is the integer returned by main() function. If you want to make the exit code of you application as 1 if success, then return 1 from main(). Hope its clear now. 
Regards,
Jijo.
_____________________________________________________
http://weseetips.com[ ^] Visual C++ tips and tricks. Updated daily.
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Return value is usually a meaningful info given back to the caller, hence the exact meaning of '0' or '1' (or whatever) is (usually again) a matter of convention between the caller and the called. For instance the return value of the 'special' C main function is, by convention 0 on success and nonzero on failure.
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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tasumisra wrote: i told him that it return 0 means code have no run time error and if its return 1 it has some error ...
There is nothing offical that says it has to be this way. It's all up to the sender and receiver as to what the values mean.
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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thanks you all for replies..
i am still not able to understand .. who is this sender reciever...how this communication is happening..
Thank you...
vikas da
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tasumisra wrote: who is this sender reciever...
This is a very basic programming question. In fact, it is communication in its simplest form. When two objects communicate, the "codes" they send back and forth only have meaning to the two objects involved. While some codes are standard, others are not. For example, code 5 from the computer in a Chevrolet may indicate an error in the oxygen sensing unit, while code 5 from the computer in a Dodge may indicate an error in the transmission.
What exactly are you fishing for?
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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DavidCrow wrote: For example, code 5 from the computer in a Chevrolet may indicate an error in the oxygen sensing unit, while code 5 from the computer in a Dodge may indicate an error in the transmission.
Oh, US are great!
The 'computer' of my car has just a boolean return value: the fuel warning light...
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 alot...i understand now...
vikas da
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Hi,
I was wondering how can i determine if there a registry key is valid or not.
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Well, that largely depends on your definition of "valid".
It is a crappy thing, but it's life -^ Carlo Pallini
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Thats fair enough.If i want to access the registry key value then it should allow me to access it.
Something which registry cleaner software uses to determine whether to delete the registry key or not.
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gayatri.neelema wrote: Something which registry cleaner software uses to determine whether to delete the registry key or not.
Keys and values are deleted based on a set of rules. And a rule used for one key may not be valid for some other key. Some keys/values may refer to file system paths. If the specified path does not exist, then the key/value may be invalid. Other keys/values refer to GUIDs that may not exist. If a key/value does not refer to anything or just has a value (e.g., 17), can it be deleted? Only the author of such knows for sure.
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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hey thanks for your reply.
But even rules cannot be formed just like tat.
I was curious to know if there were any such algorithm .so that i can use it.
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Well, there's no such thing called "registry cleaning" and most of those software are nothing more than a pile of crap.
As David clearly stated, how could anyone else other than the author (the app who wrote the key and values) possibly know that the key is "invalid" or "unwanted"? And there is no such algorithm available which decides this. If you need one, you must think of all the possibilities and devise your own algorithm.
A slight mistake that a registry cleaning software can cause devastating results. May be on operating systems like Win95 or 98, you could possibly get a very marginal benefit by deleting the registry keys that are unused. But with more recent versions, the OS is smart enough and you will almost get NO benefit just be deleting some registry keys that aren't used. If you have a different opinion (with some kind of proof or benchmarking tests done), I'll be interested in hearing from you.
After all, if you don't know much about how and what kind of cleaning operations should be performed on the registry, you must not be writing such a software.
It is a crappy thing, but it's life -^ Carlo Pallini
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While it's not an answer to your question, take a look at this article. It shows how to remove registry entries that are known to be bad. That should clue you in as to why you can't just willy nilly remove registry entries without knowing what they are for.
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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i think thats a useful ans.
thanks for your help.
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I have created a SDI application with CFormView in VS 2005, vc++, MFC. I placed listctrl, a group box, and a couple of buttons and textboxes in the group box. I am setting the list ctrl and group box posisions at runtime using SetWindowPos(). The list control and the group box sets as per my x,y values. But the control which i have palced in the group box are not set with the group box. They are there, where i have placed them statically. I want all the control placed in the group box to be set as i change the pos of the group box. Is it possible. If yes where am i doing wrong.
Thank you.
Saadhinchaali
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A groupbox is just a control like any other (with a big hole in it). Just because you place controls inside of it in the dialog editor it won't be the parent of those controls. So as far as i know you can't move the controls visibly inside the gorup box by just moving the group box itself, you have to move the controls individually inside the group box. You could try doing 4 things i think:
1. Move the controls individually - not too nice but works
2. Put the controls which are inside of the groupbox on some custom-made panel and move that one around, so you only have to move the groupbox and the panel representing its inside. - a bit complicated, not too nice, but works
3. Put the groupbox and the controls visually inside it onto a panel (like a child dialog for exmaple) and move that one around - a bit less complicated than 2. but still not nice
4. Write some helper class that walks thorough the controls which are inside the gorup box and moves them around, maybe a class inherited from the groupbox class. - I'd chose this one, you are still moving around the controls individually but you get a reusable way to do so. You would need for example an array into which you'd place the controls that need to be moved simulteniously, you could also make a method for it that collects the controls inside the group box by checking their positions.
I hope this all helps,
good luck.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
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