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From: Peter Dufault <dufault@hda.com>
Message-Id: <199701081012.FAA03591@hda.hda.com>
Subject: Re: #include file xref philosophy
In-Reply-To: <199701080136.MAA12519@godzilla.zeta.org.au> from Bruce Evans at "Jan 8, 97 12:36:31 pm"
To: bde@zeta.org.au (Bruce Evans)
Date: Wed, 8 Jan 1997 05:12:30 -0500 (EST)
Cc: hackers@freebsd.org
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> >Is there any reason for not following the posix line and having
> >include files resolve all their own dependencies? I'm talking about
> 
> That's not the ANSI C line.  POSIX.1 requires <sys/types.h> to be
> included before including any other POSIX header.

How about "POSIX.1 sometimes requires that <sys/types.h>
be included before including some POSIX headers".  They sprinkle
size_t all over the place so that old programs don't break.

Annex C has a summary of what types are defined in each header:

mqueue.h     mqd_t
semaphore.h  sem_t
signal.h     sig_atomic_t sigset_t siginfo_t
stddef.h     ptrdiff_t size_t wchar_t
stdio.h      fpos_t size_t FILE
stdlib.h     div_t ldiv_t size_t wchar_t
string.h     size_t
times.h      clock_t
sys/types.h  dev_t ino_t nlink_t pid_t ssize_t gid_t mode_t off_t size_t uid_t
termios.h    cc_t speed_t tcflag_t
time.h       clockid_t size_t time_t clock_t timer_t

So size_t is defined by stddef.h, stdio.h, stdlib.h, string.h, sys/types.h,
and time.h while off_t is only in sys/types.h.

(This is P1003.1b-1993)

-- 
Peter Dufault (dufault@hda.com)   Realtime Machine Control and Simulation
HD Associates, Inc.               Voice: 508 433 6936