Help, want to get access to my modem using CreateFile.

[SilentJackqh]

I want to get Access to my modem (COM3).
I use CreateFile Function.
HANDLE hFile=CreateFile("\\\\.\\COM3" ,READ_CONTROL,FILE_SHARE_WRITE,NULL,OPEN_EXISTING,
FILE_ATTRIBUTE_SYSTEM,NULL);

It's return INVALID_HANDLE_VALUE.
Anyone can help what should I change ?

[rxbagain]

HANDLE hFile = CreateFile("COM3",
GENERIC_READ | GENERIC_WRITE,
0, // comm devices must be opened w/exclusive-access
NULL, // no security attributes
OPEN_EXISTING, // comm devices must use OPEN_EXISTING
0, // not overlapped I/O
NULL // hTemplate must be NULL for comm devices
);
Hope this will help you

[SilentJackqh]

it's work.
how can I detect my connection still alive without distrub the connection itself ?
Is there any function to do this,
I am using VC++ v6.0 in Windows 98.

[rxbagain]

Use ClearCommError. I don't know the exact value of lpErrors for modems but I'm quite sure it's the right function as what I was doing with serial printers.

Try also GetCommModemStatus.

Hope this will help you

[SilentJackqh]

I mean what if other application already used the modem, and the Application I make is only to detect if the connection still alive or not.

[SilentJackqh]

I manage to find a function for that :
bReturn=InternetCheckConnection(NULL,0,0);

but I still cann't do it rightly.
Wheter I connect to internet or not it's still return FALSE;

[Caprice]

The CreateFile returns an error if an another application works with your modem.
If you want to check internet connection you can read about IsNetworkAlive function or GetConnectedState (something like this)

[SilentJackqh]

thanx it's works.