C / C++ / MFC

Re: how to get port number

21-Sep-07 2:57

p_ wrote:
...port which is in bold does not work...

Which is all but totally meaningless.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Dave Kreskowiak21-Sep-07 12:42

Dave Kreskowiak

21-Sep-07 12:42

Guy, if you don't know the port number of the service you're trying to connect to on the server, we're not going to be able to tell you. After all, you haven't said anything about this service so we don't know what it is you're trying to connect to!

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

COM port problems

Cedric Moonen20-Sep-07 22:59

Cedric Moonen

20-Sep-07 22:59

Hello !

I was having some troubles with the use of COM ports on an embedded device (Pocket PC with windows mobile 5). I already opened a discussion here[^].

I finally decided to use WaitCommEvent to monitor incoming data but this doesn't seem to work as expected. The port that I'm working with is a virtual COM port which is provided by a Bluetooth stack when a Bluetooth connection is established. Here is the code:

int CSerialDriver::ReadData(char* szData, int MaxLenght)
{
	DWORD dwMask = 0;
	WaitCommEvent(m_hCOMPort,&dwMask,NULL);

	if (dwMask & EV_RXCHAR)
	{
		DWORD dwRead = 0;
		int Count = 0;
		do
		{
			Count = MaxLenght - BytesRead;
			ReadFile(m_hCOMPort,szData+BytesRead,Count,&dwRead,NULL);
			BytesRead += dwRead;
		} while ( dwRead && (BytesRead<MaxLenght) );
	}

	return BytesRead;
}

The comm mask is set when the port is opened:

SetCommMask(m_hCOMPort,EV_RXCHAR);

The problem that I encounter is that the WaitCommEvent doesn't work as expected: when I receive data, WaitCommEvent exit as expected but sometimes, all the data has not been received yet (which is logical). That's not a problem because my function will get called until all data has been received. The problem comes when I enter the function a second time and call WaitCommEvent, at this time it doesn't exit even if bytes have been received in between. Having read this article[^], WaitCommEvent should exit if bytes have been received in between.

Would it be possible that it is a bug in the driver supplied by the company that produce the Bluetooth stack ? Or did I do something wrong ?

Another question: it is stated in MSDN:

Only one WaitCommEvent can be used for each open COM port handle. This means that if you have three threads in your application and each thread needs to wait on a specific comm event, each thread needs to open the COM port and then use the assigned port handle for their respective WaitCommEvent calls.

(see here[^])

So, that would mean that your application could open the COM port several time. I tried that on win32 but that doesn't work at all (each time I receive an invalid handle value and the GetLastError code is "Access is denied"). I tried with different access:

m_hCOMPortWrite = CreateFile(strPortName.c_str(),
				GENERIC_WRITE,
			        FILE_SHARE_READ | FILE_SHARE_WRITE,
			 	NULL,
				OPEN_EXISTING,
				0,
				NULL);

m_hCOMPortRead = CreateFile(m_strPortName.c_str(),
			GENERIC_READ ,
			FILE_SHARE_READ | FILE_SHARE_WRITE,
			NULL,
			OPEN_EXISTING,
			0,
			NULL);

Is there a difference here between win32 and windozs Mobile 5 ? Why do they state that you could open the port multiple time ?

Thanks in advance

Cédric Moonen
Software developer

Charting control [v1.2]

Calling java method from c++ ! stuck in between while invoking jvm!

amitamit19820-Sep-07 22:50

amitamit198

20-Sep-07 22:50

//Its tt.java simple Helloworld program .which i am willing to call from c++
// i created .class and .h file of it !

public class tt {
public static void main(String[] args) {
System.out.println("Hello World ");
}
}

//*****************************************************************************************

//i wrote it in vc++ 6.0
//for this i added path of tt.h(created using javah) in preprocessor path(underprojects=>setting=>c/c++ tab)
//then added path of jvm.lib (under projects=>setting=>link tab)

#include "jni.h"
#define PATH_SEPARATOR ';' /* define it to be ':' on Solaris */
#define USER_CLASSPATH "C:\j2sdk1.4.2_05\bin" /* where tt.class is */

int main()
{
JNIEnv *env;
JavaVM *jvm;
jint res;
jclass cls;
jmethodID mid;
jstring jstr;
jclass stringClass;
jobjectArray args;;
JavaVMInitArgs vm_args;;
JavaVMOption options[1];
options[0].optionString ="-Djava.class.path="USER_CLASSPATH;
vm_args.version = 0x00010002;
vm_args.options = options;
vm_args.nOptions = 1;
vm_args.ignoreUnrecognized = JNI_TRUE;
/* Create the Java VM */
res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);

if (res < 0) {
fprintf(stderr, "Can't create Java VM\n");
// exit(1);
}
cls = (env)->FindClass("tt");
if (cls == 0) {
// goto destroy;
}

mid = (env)->GetStaticMethodID(cls, "main","([Ljava/lang/String;)V");
if (mid == 0) {
// goto destroy;
}
jstr = (env)->NewStringUTF(" from C!");
if (jstr == 0) {
// goto destroy;
}
stringClass = (env)->FindClass("java/lang/String");
args = (env)->NewObjectArray(1, stringClass, jstr);
if (args == 0) {
// goto destroy;
}
(env)->CallStaticVoidMethod(cls, mid, args);

//destroy:
if ((env)->ExceptionOccurred()) {
(env)->ExceptionDescribe();
}
(jvm)->DestroyJavaVM();
return 0;
}

/// After doing that much ! i got this LINKING TIME ERRORs

--------------------Configuration: ltry - Win32 Debug--------------------
Compiling...
Skipping... (no relevant changes detected)
tr.cpp
Linking...
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/ltry.exe : fatal error LNK1120: 1 unresolved externals

// please help me sir....what chages i should do so that it gets run n calls java method ?

Re: Calling java method from c++ ! stuck in between while invoking jvm!

Cedric Moonen20-Sep-07 23:23

Cedric Moonen

20-Sep-07 23:23

You probably are trying to create a Win32 application and you provide a main function instead of a WinMain. You should create a console application instead.

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Calling java method from c++ ! stuck in between while invoking jvm!

David Crow21-Sep-07 2:55

How to write in windows registry

21-Sep-07 2:55

See here.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Exelioindia20-Sep-07 21:00

20-Sep-07 21:00

Hi all,

I am new to VC++, I am developing an dll file using VC++, in this i want to put an entry in my windows registry. For example:

SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\\test\\test , in this path i want to write some value in the key test.

Plese suggest me

Thanks in advance

Know is Drop, Unknown is Ocean

Llasus20-Sep-07 21:12

Llasus

20-Sep-07 21:12

Use RegCreateKeyEx for creating the path in the registry, the second parameter is where you'll set the path that you said. You can create the values in your registry by using RegSetValueEx. RegCloseKey will close the registry item that you opened.

Exelioindia20-Sep-07 21:50

20-Sep-07 21:50

Thanks for your suggestion. Dnt mistake me, plz give me some sample code's or link to learn this.

Thankyou once again

Know is Drop, Unknown is Ocean

Llasus20-Sep-07 22:02

Llasus

20-Sep-07 22:02

Go to MSDN for the details. http://msdn2.microsoft.com/en-us/default.aspx
I found an article by Naren Neelamegam that has an example. Just search for it there. Here is the link: http://www.codeproject.com/system/Tips_And_Tricks.asp

Exelioindia21-Sep-07 0:09

21-Sep-07 0:09

Thankyou very much for your kindly help

Know is Drop, Unknown is Ocean

David Crow21-Sep-07 2:51

21-Sep-07 2:51

Exelioindia wrote:
plz give me some sample code's or link to learn this.

Is that something you are incapable of?

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

nbugalia20-Sep-07 21:28

nbugalia

20-Sep-07 21:28

You can also try for -

CWinApp::WriteProfileInt/CWinApp::WriteProfileString and CWinApp::GetProfileInt/CWinApp::GetProfileInt

Exelioindia20-Sep-07 21:50

20-Sep-07 21:50

Thanks for your suggestion. Dnt mistake me, plz give me some sample code's or link to learn this.

Thankyou once again

Know is Drop, Unknown is Ocean

Hamid_RT20-Sep-07 21:57

Hamid_RT

20-Sep-07 21:57

See A registry Class [^]

ThatsAlok20-Sep-07 23:08

ThatsAlok

20-Sep-07 23:08

for me CRegKey class provided by Atl is best!

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Rahul Vaishnav21-Sep-07 1:03

Rahul Vaishnav

21-Sep-07 1:03

Use below function

BOOL WriteToRegistry(HKEY hRegRootPath, CString strRegPath, CString strRegAttribute, long lValue)
{
CRegKey key;
CString strAttributeValue;
strAttributeValue.Format("%u", lValue);
if(key.Create(hRegRootPath, strRegPath) == ERROR_SUCCESS)
{
if (key.SetValue(strAttributeValue,strRegAttribute) == ERROR_SUCCESS)
{
key.Close();
return TRUE;
}
}
return FALSE;
}

call the function as shown in example below...

WriteToRegistry(HKEY_LOCAL_MACHINE, "SOFTWARE\\ABC\\DEF", "NUM",1);

Rahul Vaishnav

Exelioindia21-Sep-07 1:33

21-Sep-07 1:33

Thanks for your code. I am getting some error with the above code. Is this an VC++ code?, sorry if i am wrong.

Errors:

error C2061: syntax error : identifier 'CString'
error C2065: 'CRegKey' : undeclared identifier
error C2065: 'CString' : undeclared identifier
error C2065: 'key' : undeclared identifier
error C2065: 'lValue' : undeclared identifier
error C2065: 'strAttributeValue' : undeclared identifier
.............

Any header files has to included?

Thankyou once again

Know is Drop, Unknown is Ocean

David Crow21-Sep-07 2:49

21-Sep-07 2:49

Exelioindia wrote:
Is this an VC++ code?,

If you have to ask such a question, then a project involving the registry is way beyond your grasp. Start with something less ambitious, please!

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[Message Deleted]

Californian221-Sep-07 5:57

Californian2

21-Sep-07 5:57

[Message Deleted]

David Crow21-Sep-07 6:07

21-Sep-07 6:07

Californian2 wrote:
He's rude to everybody...

If my bluntness offends you, ignore it. You'll find that my sentiments (toward newbie laziness) are supported by the professionals. If I said something that was indeed incorrect, I'll admit such, and have done so in the past.

Californian2 wrote:
...when he tried...

Note the operative word "tried." I certainly don't claim to know any answer, but I do give most of them a try. As a matter of fact, I spent nearly ten minutes reproducing the question of which you speak, and my suggestion was spot on. While Mark's suggestion was more in with what you were after, that just supports the old adage of there being more than one way to skin a cat.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne