Date: Mon, 12 Feb 1996 16:59:10 -0500
From: Andrew Szymkowiak <aes AT rosserv DOT gsfc DOT nasa DOT gov>
To: djgpp AT delorie DOT com
Subject: maximum number of open files (in V2.00)

In a recent posting (on another subject), Charles Sandman said:

> The default setup will handle up to 255 handles, so you can open like 249
> files.  Yes, I tested it and was able to open this many.  No changes 
> should be required, except a files statement in the config.sys (make it
> at least 60).

I have just started getting the ENFILE error (or is it "EMFILE"? - I
think that maybe it is one way in the code, and another way in the
info), with far fewer than 249 files.  My config.sys value is
sufficiently large.  When I look through the source, I find a manifest
constant with a name like FILE_REC_MAX #define'd to the value 20 (in a
file somewhere like ../include/libc/local.h - sorry to be vague but I
am not near my DOS machine).  It is my impression that this may be a
limit.  I have not yet tried to re-build the library after changing
this define, though will do so shortly.  in the meantime, I wonder if
this must really be a fixed size?  I would think that either the
start-up code could look up the DOS value, and malloc to match it, or
that the _alloc_file function could malloc more descriptor space "on
the fly".  Since I did not study the code, there are probably good
reasons why this could not be done, but in my ignorance, it looks
possible.
  Keep up the good work,
     Andy Szymkowiak
     X-ray Astrophysics Branch
     NASA/GSFC