<pthread.h> includes

[Bruce Evans]

On Fri, 19 Aug 2005, Stefan Farfeleder wrote:

> I think some of the headers included by <pthread.h> violate the POSIX
> specification (I'm looking at SUSv3/POSIX 1003.1 2004) by making more
> symbols visible than allowed.
>
> <sys/cdefs.h>		Ok
> <sys/types.h>		Ok
> <sys/_pthreadtypes.h>	Ok
> <sys/time.h>		No? (POSIX allows <time.h> which is a subset)
> <sys/signal.h>		No?
> <limits.h>		No?
> <sched.h>		Ok
>
> Is this correct?  Should it be fixed?

All of these includes except <sys/cdefs.h> and <sys/pthreadtypes.h> are
wrong IMO:

<sys/cdefs.h>		needed, but can be obtained as a side effect
 			of including almost any other header in the list.
<sys/types.h>		only used to declare size_t.  We handle this better
 			in many other headers.  The old draft of POSIX that
 			I'm looking at doesn't say that <pthread.h> declares
 			size_t, so it might be conformant to use __size_t
 			in the prototypes.
<sys/_pthreadtypes.h>	Ok
<sys/time.h>		only used to declare sigset_t and struct timespec.
 			We have a whole header, <sys/_sigset.h>, to help
 			declare sigset_t better (it only declares __sigset_t),
 			and use it in many other headers.  We have 2 headers,
 			<sys/timespec.h> and <sys/_timespec.h>, just to
 			declare struct timespec, and use them in many other
 			headers.  Here we only need a forward declaration of
 			struct timespec or maybe struct __timespec, modulo
 			POSIX bugs.  It is a bug in POSIX that <time.h> is
 			allowed.  The old draft of POSIX doesn't say that
 			<pthread.h> declares sigset_t or struct timespec
 			(just that it may declare the latter).  This is
 			unlike what it says for other headers.  E.g., we
 			use <sys/timespec.h> in <sys/select.h> to satisfy
 			the POSIX mistake that a complete struct timespec
 			must be declared there.
<sys/signal.h>		Just namespace pollution.
<limits.h>		Just namespace pollution.
<sched.h>		only used to declare struct sched_param and to
 			satisfy a POSIX mistake.  A forward declaration
 			would suffice.

POSIX should say that size_t, sigset_t and struct timespec are completely
declared, and then it would say that [low quality] implementations may
declare everything else in the primary headers that declare these.

Bruce