Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!hc!lll-winken!lll-crg.llnl.gov!casey
From: casey@lll-crg.llnl.gov (Casey Leedom)
Newsgroups: comp.windows.x
Subject: Small problem with lib/Xt/fd.h and 4.3BSD + FIX
Message-ID: <16287@lll-winken.UUCP>
Date: 5 Jan 89 08:49:05 GMT
Sender: usenet@lll-winken.UUCP
Reply-To: casey@lll-crg.llnl.gov (Casey Leedom)
Organization: Lawrence Livermore National Laboratory
Lines: 31


  I haven't seen this mentioned before, so I'll post it.  The problem
occurred on a VAX 785 running 4.3BSD + all BSD patches + 1988 April
networking code.  I've checked the stock 4.3BSD source code and you'd run
into the problem there too.

  Essentially fd.h and <sys/types.h> both define the typedef fd_set.  My
patch uses a test of the defined status of NFDBITS to determine whether
or not fd_set has been typedef'd.  Unfortunately C doesn't provide a
mechanism to test for the existence of typedef's.  I don't like my fix,
but I think it should work on most systems.  Fd_set and NFDBITS came into
existence at the same time.

Casey

-----
*** fd.h-dist	Tue Sep  6 13:29:39 1988
--- fd.h	Wed Jan  4 23:57:44 1989
***************
*** 42,49 ****
--- 42,51 ----
  #define	FD_SETSIZE	256
  #endif
  
+ #ifndef NFDBITS
  typedef long fd_mask;
  #define NFDBITS	(sizeof(fd_mask) * NBBY)	/* bits per mask */
+ #endif
  #ifndef howmany
  #define	howmany(x, y)	(((x)+((y)-1))/(y))
  #endif