🚀 go-pugleaf

Il Fri, 25 Jan 2008 12:47:43 +0100, "Anton" <acvoosten@zeelandnet.nl> ha scritto:

[snip]
>However when I try to open the USB-to Serial Port (COM11 etc) from my GPS 
>CreateFile fails.
[snip]

You have to put the prefix \\.\ in front of the COM[n] string. 

For example: "\\\\.\\COM11".

Regards

Thank you very much, how simple can it be.

But,......

With a few of those existing virtual ports which are not really active, it 
takes more then 10 seconds to open them and that's just the thing I want to 
avoid.
Maybe there's a timeout you can set or something else?

Thanks again,

Regards

Anton



"Giuliano" <nonfracassatelepalline@non_fracassate_le_pall.ine> schreef in 
bericht news:njkjp3d5feaailo8p568elmqhntg8br1ku@4ax.com...
> Il Fri, 25 Jan 2008 12:47:43 +0100, "Anton" <acvoosten@zeelandnet.nl> ha 
> scritto:
>
> [snip]
>>However when I try to open the USB-to Serial Port (COM11 etc) from my GPS
>>CreateFile fails.
> [snip]
>
> You have to put the prefix \\.\ in front of the COM[n] string.
>
> For example: "\\\\.\\COM11".
>
> Regards 

Il Fri, 25 Jan 2008 14:26:01 +0100, "Anton" <acvoosten@zeelandnet.nl> ha scritto:

[snip]
>With a few of those existing virtual ports which are not really active, it 
>takes more then 10 seconds to open them and that's just the thing I want to 
>avoid.
>Maybe there's a timeout you can set or something else?
[snip]

Hi Anton

    ten seconds? Uhm... I never seen a such behaviour when opening a com port. 
For example, AFAIK, if the USB of a virtual COM port is unplugged, the port simply
disappears. However, I use the following code to detect if a comport exists and if it's
available. The fn returns true if the com exists and set the 2nd parameter to true
if it's busy.

bool IsComPortAvailable( int PortNumber, bool& InUse )
{
    AnsiString const ComName = AnsiString( "\\\\.\\COM" ) + PortNumber;

    HANDLE const hComm =
        CreateFile(
            ComName.c_str(),
            GENERIC_READ | GENERIC_WRITE,
            0,
            0,
            OPEN_EXISTING,
            0,
            0
        );

    if ( hComm == INVALID_HANDLE_VALUE ) {
        DWORD const dwError = GetLastError();
        if ( dwError == 5 )  // Port exists, but cannot be opened
            InUse = true;
        else if ( dwError == 2 )  // Port does not exist
            return false;
    }
    else {
        CloseHandle( hComm );
        InUse = false;
    }

    return true;
}

Regards

Giuliano

"Giuliano" <nonfracassatelepalline@non_fracassate_le_pall.ine> wrote in 
message news:vegkp3hhb89k52eol1c49492gc46k3iedv@4ax.com...

>        if ( dwError == 5 )  // Port exists, but cannot be opened
>            InUse = true;
>        else if ( dwError == 2 )  // Port does not exist
>            return false;

Rather than checking for numeric literals, you should use the predefined 
constants in winerror.h instead, so you can see what the code is actually 
checking for, ie:

    if ( dwError == ERROR_ACCESS_DENIED )  // Port exists, but cannot be 
opened
        InUse = true;
    else if ( dwError == ERROR_FILE_NOT_FOUND )  // Port does not exist
        return false;


Gambit

Hello  Giuliano,

Let me explain:

I installed a bluetooth dongle and became 9 serial blue tooth ports, some 
are only for reading, others just for writing.
I'm not quite sure how everyhing works, the menuitmes are in Chinese and 
that's a little diificult for me.

But in contrast with a 'normal'  usb to serial plug, those ports dont's 
disappear after the dongle is unplugged
They are visible in the hardware-view and in the windows register.

So the software thinks the ports are present, tries to open them and maybe 
that's the reason it takes such a long time.

But even if the dongle is plugged in it takes some time to detect which 
ports are in use.

In fact I'm using then API232 functions like sio_open, but the results are 
the same.

Regards,

Anton






"Giuliano" <nonfracassatelepalline@non_fracassate_le_pall.ine> schreef in 
bericht news:vegkp3hhb89k52eol1c49492gc46k3iedv@4ax.com...
> Il Fri, 25 Jan 2008 14:26:01 +0100, "Anton" <acvoosten@zeelandnet.nl> ha 
> scritto:
>
> [snip]
>>With a few of those existing virtual ports which are not really active, it
>>takes more then 10 seconds to open them and that's just the thing I want 
>>to
>>avoid.
>>Maybe there's a timeout you can set or something else?
> [snip]
>
> Hi Anton
>
>    ten seconds? Uhm... I never seen a such behaviour when opening a com 
> port.
> For example, AFAIK, if the USB of a virtual COM port is unplugged, the 
> port simply
> disappears. However, I use the following code to detect if a comport 
> exists and if it's
> available. The fn returns true if the com exists and set the 2nd parameter 
> to true
> if it's busy.
>
> bool IsComPortAvailable( int PortNumber, bool& InUse )
> {
>    AnsiString const ComName = AnsiString( "\\\\.\\COM" ) + PortNumber;
>
>    HANDLE const hComm =
>        CreateFile(
>            ComName.c_str(),
>            GENERIC_READ | GENERIC_WRITE,
>            0,
>            0,
>            OPEN_EXISTING,
>            0,
>            0
>        );
>
>    if ( hComm == INVALID_HANDLE_VALUE ) {
>        DWORD const dwError = GetLastError();
>        if ( dwError == 5 )  // Port exists, but cannot be opened
>            InUse = true;
>        else if ( dwError == 2 )  // Port does not exist
>            return false;
>    }
>    else {
>        CloseHandle( hComm );
>        InUse = false;
>    }
>
>    return true;
> }
>
> Regards
>
> Giuliano
> 

Il Sat, 26 Jan 2008 11:32:08 +0100, "Anton" <acvoosten@zeelandnet.nl> ha scritto:

>Hello  Giuliano,
>
>Let me explain:
>
>I installed a bluetooth dongle and became 9 serial blue tooth ports, some 
>are only for reading, others just for writing.
>I'm not quite sure how everyhing works, the menuitmes are in Chinese and 
>that's a little diificult for me.
>
>But in contrast with a 'normal'  usb to serial plug, those ports dont's 
>disappear after the dongle is unplugged
>They are visible in the hardware-view and in the windows register.
>
>So the software thinks the ports are present, tries to open them and maybe 
>that's the reason it takes such a long time.
>
>But even if the dongle is plugged in it takes some time to detect which 
>ports are in use.
>
>In fact I'm using then API232 functions like sio_open, but the results are 
>the same.

Hi Anton

    it seems a problem caused by a bad design of the BT serial port. Have you tried 
to contact the manufacturer to ask for explanations? In my opinion, you don't have many
chances to resolve the problem with the standard API. If the supplier can furnish you the
access to a deepest layer, for example with a specific DLL, maybe you can have more
control upon the process to open a port.

Regards

Giuliano

Hi Anton,

> 
> I installed a bluetooth dongle and became 9 serial blue tooth ports, some 
> are only for reading, others just for writing.
> I'm not quite sure how everyhing works, the menuitmes are in Chinese and 
> that's a little diificult for me.
> 
> But in contrast with a 'normal'  usb to serial plug, those ports dont's 
> disappear after the dongle is unplugged
> They are visible in the hardware-view and in the windows register.
> 
> So the software thinks the ports are present, tries to open them and maybe 
> that's the reason it takes such a long time.
> 

I also have a COM-port detecting function and I discovered this kind of 
problem on some Laptops with virtual Bluetooth ports. I know that nobody 
wants to disable these virtual ports just to start our software.
So the only way to solve this was to start a own thread for every port 
and to kill the thread (the hard way) if it took too long to respond.
Not very nice but it works reliable.

Bye,

-- 
Dipl. Ing. Oliver Rutsch
EMail: orutsch@sympatec.com
Sympatec GmbH

Thank you all for your tips.

I discovered the problem is caused by the software. I've downloaded other 
software and the serial ports are detected immediately even when I unplug 
the dongle.

But that's just a solution for me, cause in fact I make the program for 
other, unknown people and when they don't use the correct software they may 
have the same problems and blame it to my program.

So the idea to start a thread to detect the comm-ports does not seem so bad 
to me.
I'll think about it.

Thanks and regards,


Anton









"Oliver Rutsch" <orutsch@sympatec.com> schreef in bericht 
news:479d85db$1@newsgroups.borland.com...
> Hi Anton,
>
>>
>> I installed a bluetooth dongle and became 9 serial blue tooth ports, some 
>> are only for reading, others just for writing.
>> I'm not quite sure how everyhing works, the menuitmes are in Chinese and 
>> that's a little diificult for me.
>>
>> But in contrast with a 'normal'  usb to serial plug, those ports dont's 
>> disappear after the dongle is unplugged
>> They are visible in the hardware-view and in the windows register.
>>
>> So the software thinks the ports are present, tries to open them and 
>> maybe that's the reason it takes such a long time.
>>
>
> I also have a COM-port detecting function and I discovered this kind of 
> problem on some Laptops with virtual Bluetooth ports. I know that nobody 
> wants to disable these virtual ports just to start our software.
> So the only way to solve this was to start a own thread for every port and 
> to kill the thread (the hard way) if it took too long to respond.
> Not very nice but it works reliable.
>
> Bye,
>
> -- 
> Dipl. Ing. Oliver Rutsch
> EMail: orutsch@sympatec.com
> Sympatec GmbH