Original from  Jonathan de Boyne Pollard  to Denis Tonn on 11-01-1996
Original Subject: watcom and warp

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 DT>
   >  Under OS/2, there is no "user defined system limit" for
open files,
   > but there is still an application default limit of 20 handles (same
   > as for Dos applications under real Dos). The application still has to
   > do some work to open more than 20 handles.
 DT>
 
JP>   As reported by DosSetRelMaxFH with a delta of 0, the default is 50 on
JP>   OS/2 Warp 3.0, not 20.  The CP Reference is wrong.

 Interesting.. I have not checked this in a long time, but after your 
message I used Theseus to take a quick look at quite a few apps 
running under Warp Connect and also Warp 4. Most showed a "MaxFH of
20" according to Theseus. The exceptions seemed to have values of 512,
256, and 100 (which would imply that they set a higher value for the 
process). 

 I don't have a compiler handy (something had to give to install Warp
4 on this laptop) - so I can't duplicate your exact test at the 
moment. 

 I do have a couple of dumps that were taken at 8.209 (Warp Connect GA
level) and JFN_TABLE is still only 40 (decimal) bytes long which would
indicate that the default for a process is still 20 handles (each 
handle takes a word location). I also doublechecked that JFN_PTABLE 
still points to this table for the process (it will point to a new 
memory segment after the app does a DosSetMaxFH call). 
 If the "default" has been expanded in Warp 3, I would have expected 
to see a larger JFN_TABLE or new pointer in JFN_PTABLE for the
process. If they failed to use these pointers and locations at all in
Warp 3, the techniques that I use to find open files per process (in a
dump or KDB session) would fail badly - and they still work fine. All
in all, I would be prepared to state that I think the CP Ref is still
correct for Warp 3 - and even Warp 4. 

 I am not sure what and how your system is setup, but it looks like a 
parent process is starting your app with it's enviroment (including 
file handles) as "inherited" or that the runtime library of your code 
is doing the setup for you.
 You should be able to see if the runtime for your app is setting this
up for you with the system trace facility. Make sure you have a 
tracebuf=63 (any value up to 63) in your config.sys and start the 
trace with TRACE ON KERNEL(142,299,414,415). Run your app, and then 
use TRACEFMT to view the trace entries (if any). It will tell you if 
the runtime is setting a higher value before your code gets control. 
 
 

   Denis       

 Certified OS/2 Engineer, Certified OS/2 Instructor, Certifiable....
 All opinions are my very own, IBM has no claim upon them
 
.
--- Maximus/2 3.01