Subj : Serial port query
To : Vitus Jensen
From : Darin McBride
Date : Sun Aug 06 2000 04:12 pm
Hello Vitus!
Replying to a message of Vitus Jensen to Darin McBride:
DM>> I've been asked how to do something I'm at a loss as to where to
DM>> start - if it's possible at all. To quote the person asking me:
DM>> Is there a way 1. to check the state of a port, 2. determine the
DM>> application using it?
DM>> By #1, I believe he means "determine if a comm port was in use".
DM>> Any ideas whatsoever would be appreciated. I believe #1 can be done
DM>> by an attempt to open the port as a file in "DENY_ALL" mode - if it
DM>> fails, someone is using it. I don't believe #2 is possible. If I
DM>> could be corrected, that would be great. :-)
VJ> Get OS2UNDOC from hobbes and have a look at the DosQuerySysState API.
VJ> It will return infos about all open files of a single or all
VJ> processes. There are problems when using it at certain fixpak levels
VJ> (older Warp 3 fixpaks).
Of course! I forgot all about that. I already use that call for a number of
things, so one more is no biggie. :-) Unfortunately, I can't figure out how
to trace back from the file to the process(es). I've done some slight
modifications to the sample programs given in the undoc INF file, and I get:
PID: 1736
PPID: 30
type: 3
state: 10
session id: 36
mod handle: 1be8 (D:\BBS\FLEET\FLTSTRT.EXE)
# of threads: 4
[...]
I just can't tell how to get from one to the other.
VJ> And Scott Garfinkle posted in C.O.O.P.Misc that it is now possible
VJ> getting infos about all open semaphore handles as well. Starting
VJ> with FP 13 AFAIR (got the msg stored somewhere).
DQSS doesn't seem to get 32-bit sem handles yet... :-( 16-bit doesn't seem to
be a problem. (I recently installed FP14.)
