Replying to a message of Peter Schuller to Mikko Hyvarinen:

 MH>> OS/2 handles COM ports as files. So, when the BBS program passes you
 MH>> a COM handle, you can use it via DosWrite and DosRead.

 PS> I got a "tip" on that, tryed that, but I didn't get it to
work, this
 PS> is what a did

 PS>    HFILE hCom = 0L;
 PS>    ULONG ulAction = 0;
 PS>    ULONG ulBytesRead = 0;
 PS>    ULONG ulWrote = 0;
 PS>    ULONG ulLocal = 0;
 PS>    APIRET rc = NO_ERROR;


 PS>    rc = DosOpen (_argv[1], &hCom, &ulAction, 100L,
 PS>       FILE_NORMAL,
 PS>       OPEN_ACTION_OPEN_IF_EXISTS,
 PS>       OPEN_ACCESS_READWRITE, 0L);

 PS> But it won't work, DosOpen return 12. Maximus passes on porthandle
"5"
 PS> for COM2. Is there any specific "flag" i have to use?

DosOpen opens a file (or device) for which you give a name. Here you are
trying to open a file or device, whose name is in argv[ 1 ], which, if I
understand you correctly, is the (already open) file handle for the com
port.

So you don't have to use DosOpen at all. Just change the number held in the
string argv[ 1 ] to an integer, and you have the file handle you can read
from and write to:

HFILE ComHandle;
char pBufferArea[ 4096 ];
ULONG ulBufferLength, ulBytesRead, ulBytesWritten;
APIRET rc;

ComHandle = strtol( _argv[ 1 ], NULL, 10 ); /* assuming the handle was
passed in base 10 format */

ulBufferLength = 4096;
rc = DosRead( ComHandle, pBufferArea, ulBufferLength, &BytesRead );

ulBufferLength = strlen( pBufferArea);
rc = DosWrite( ComHandle, pBufferArea, ulBufferLength, &BytesWritten);

There is one problem with the above:
If the BBS program didn't tell the com driver to return a DosRead after a
certain period of time has expired, even if our buffer is not full yet, the
DosRead will never return until 4096 characters have been received. To
prevent this, the BBS program, right after using DosOpen to open the com
port, has to use a DosDevIoCtl call. For information on this, look up ioctl
functions, category 1 (async functions), function 0x53 (set the device
control block).

Marcel,                 Check out the baby pics; last updated on June 12, 1996:
[Team OS/2]             http://www.bright.net/~mvusse

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