Reviewed by: bde

Changes to support building with _POSIX_SOURCE set to 199309L:

1. Add sys/_posix.h to handle those preprocessor defs that POSIX
says have effects when defined before including any header files;

2. Change POSIX4_VISIBLE back to _POSIX4_VISIBLE

3. Add _POSIX4_VISIBLE_HISTORICALLY for pre-existing BSD features now
defined in POSIX.  These show up when:

_POSIX_SOURCE and _POSIX_C_SOURCE are not set or
_POSIX_C_SOURCE is set >= 199309L

and vanish when:

_POSIX_SOURCE is set or _POSIX_C_SOURCE is < 199309L.

4. Explain these in man 9 posix4;

5. Include _posix.h and conditionalize on new feature test.

4 files changed, 18 insertions, 19 deletions

diff --git a/sys/posix4/aio.h b/sys/posix4/aio.h
index 6cd47bc..678dc0f 100644
--- a/sys/posix4/aio.h
+++ b/sys/posix4/aio.h
@@ -31,15 +31,15 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id:$
+ * $Id: aio.h,v 1.1 1998/03/04 10:26:10 dufault Exp $
  */
 
 /* aio.h: P1003.1B-1993 Asynchronous I/O */
 
-#ifndef _POSIX4_AIO_H_
-#define _POSIX4_AIO_H_
+#ifndef _AIO_H_
+#define _AIO_H_
 
-#ifdef POSIX4_INCLUDE_MAYBES
+#ifdef _POSIX4_INCLUDE_MAYBES
 #include <sys/types.h>
 #include <signal.h>
 #include <time.h>
@@ -87,6 +87,7 @@ struct aiocb {
 #ifndef KERNEL
 #include <sys/cdefs.h>
 
+__BEGIN_DECLS
 int aio_read __P((struct aiocb *));
 int aio_write __P((struct aiocb *));
 
@@ -101,6 +102,7 @@ int aio_suspend __P((caio_listio_ctl [_POSIX_AIO_LISTIO_MAX],
 	int, const struct timespec *));
 
 int aio_fsync __P((int, struct aiocb *));
+__END_DECLS
 
 #endif /* KERNEL */
 
diff --git a/sys/posix4/mqueue.h b/sys/posix4/mqueue.h
index 0872ddf..6fcf440 100644
--- a/sys/posix4/mqueue.h
+++ b/sys/posix4/mqueue.h
@@ -36,7 +36,7 @@
  *
  */
 
-#ifdef POSIX4_INCLUDE_MAYBES
+#ifdef _POSIX4_INCLUDE_MAYBES
 #include <sys/types.h>
 #include <fcntl.h>
 #include <time.h>
@@ -55,8 +55,10 @@ struct mq_attr {
 };
 
 #ifndef KERNEL
+
 #include <sys/cdefs.h>
 
+__BEGIN_DECLS
 mqd_t mq_open __P((const char *, int oflag, ...));
 int mq_close __P((mqd_t));
 int mq_unlink __P((const char *));
@@ -65,6 +67,7 @@ ssize_t mq_receive __P((mqd_t, char *, size_t, unsigned int *));
 int mq_notify __P((mqd_t, const struct sigevent *));
 int mq_setattr __P((mqd_t, const struct mq_attr *, struct mq_attr *));
 int mq_getattr __P((mqd_t, struct mq_attr *));
+__END_DECLS
 
 #endif /* KERNEL */
 
diff --git a/sys/posix4/posix4.h b/sys/posix4/posix4.h
index 5037b03..99ba882 100644
--- a/sys/posix4/posix4.h
+++ b/sys/posix4/posix4.h
@@ -33,22 +33,14 @@
  *
  */
 
-#if defined(_POSIX_VERSION) && _POSIX_VERSION >= 199309L
+#include <sys/_posix.h>
+
+#ifdef _POSIX4_VISIBLE
+
 #include <sys/param.h>
 #include <sys/ioccom.h>
 #include <sched.h>
 
-/*
- * This defines POSIX4_VISIBLE to indicate posix4 extensions should show up.
- * You should test this when you add a posix4 extension to a header
- * that exists in POSIX.1.  Try "man 9 posix4".
- */
-
-#if !defined(_POSIX_C_SOURCE) || \
- defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 199309L
-#define POSIX4_VISIBLE
-#endif
-
 /* 
  *
  * March 1, 1998: Details from here on change and this header file
@@ -296,5 +288,5 @@ int kmunlock(int *, void *, const void *, size_t );
 	{ "timer_max", CTLTYPE_INT }, \
 }
 
-#endif /* _POSIX_VERSION >= 199309L */
+#endif /* _POSIX4_VISIBLE */
 #endif /* _POSIX4_POSIX4_H_ */
diff --git a/sys/posix4/semaphore.h b/sys/posix4/semaphore.h
index fbcab13..a24ac35 100644
--- a/sys/posix4/semaphore.h
+++ b/sys/posix4/semaphore.h
@@ -36,7 +36,7 @@
  *
  */
 
-#ifdef POSIX4_INCLUDE_MAYBES
+#ifdef _POSIX4_INCLUDE_MAYBES
 #include <sys/types.h>
 #include <fcntl.h>
 #endif
@@ -46,6 +46,7 @@ typedef int sem_t;
 #ifndef KERNEL
 #include <sys/cdefs.h>
 
+__BEGIN_DECLS
 int sem_init __P(sem_t *, int, unsigned int));
 int sem_destroy __P((sem_t *));
 sem_t sem_open __P((const char *, int, ...));
@@ -55,6 +56,7 @@ int sem_wait((sem_t *));
 int sem_trywait((sem_t *));
 int sem_post((sem_t *));
 int sem_getvalue((sem_t *, int *));
+__END_DECLS
 
 #endif /* KERNEL */