MFC r312934:

Make use of clang nullability attributes in C headers.

Replace uses of the GCC __nonnull__ attribute with the clang nullability
qualifiers. These are starting to get use in clang's static analyzer.

Replacement should be transparent for developers using clang. GCC ports
from older FreeBSD versions may need updating if the compiler was built
before r312860 (Jan-27-2017).

Hinted by:	Apple's Libc-1158.20.4, Bionic libc

Relnotes:	yes

5 files changed, 170 insertions, 134 deletions

diff --git a/include/err.h b/include/err.h
index b6ab214..b0e3121 100644
--- a/include/err.h
+++ b/include/err.h
@@ -43,6 +43,8 @@
 #include <sys/cdefs.h>
 #include <sys/_types.h>
 
+__NULLABILITY_PRAGMA_PUSH
+
 __BEGIN_DECLS
 void	err(int, const char *, ...) __dead2 __printf0like(2, 3);
 void	verr(int, const char *, __va_list) __dead2 __printf0like(2, 0);
@@ -58,7 +60,8 @@ void	vwarnc(int, const char *, __va_list) __printf0like(2, 0);
 void	warnx(const char *, ...) __printflike(1, 2);
 void	vwarnx(const char *, __va_list) __printflike(1, 0);
 void	err_set_file(void *);
-void	err_set_exit(void (*)(int));
+void	err_set_exit(void (* _Nullable)(int));
 __END_DECLS
+__NULLABILITY_PRAGMA_POP
 
 #endif /* !_ERR_H_ */
diff --git a/include/pthread.h b/include/pthread.h
index ff74e0b..3f45d6d8 100644
--- a/include/pthread.h
+++ b/include/pthread.h
@@ -46,6 +46,8 @@
 #include <sched.h>
 #include <time.h>
 
+__NULLABILITY_PRAGMA_PUSH
+
 /*
  * Run-time invariant values:
  */
@@ -147,28 +149,35 @@ struct _pthread_cleanup_info {
  */
 __BEGIN_DECLS
 int		pthread_atfork(void (*)(void), void (*)(void), void (*)(void));
-int		pthread_attr_destroy(pthread_attr_t *);
-int		pthread_attr_getstack(const pthread_attr_t * __restrict, 
-			void ** __restrict, size_t * __restrict);
-int		pthread_attr_getstacksize(const pthread_attr_t *, size_t *);
-int		pthread_attr_getguardsize(const pthread_attr_t *, size_t *);
+int		pthread_attr_destroy(pthread_attr_t * _Nonnull);
+int		pthread_attr_getstack(
+		    const pthread_attr_t * _Nonnull __restrict, 
+		    void ** _Nonnull __restrict,
+		    size_t * _Nonnull __restrict);
+int		pthread_attr_getstacksize(const pthread_attr_t * _Nonnull,
+		    size_t * _Nonnull);
+int		pthread_attr_getguardsize(const pthread_attr_t * _Nonnull,
+		    size_t * _Nonnull);
 int		pthread_attr_getstackaddr(const pthread_attr_t *, void **);
-int		pthread_attr_getdetachstate(const pthread_attr_t *, int *);
-int		pthread_attr_init(pthread_attr_t *);
-int		pthread_attr_setstacksize(pthread_attr_t *, size_t);
-int		pthread_attr_setguardsize(pthread_attr_t *, size_t);
-int		pthread_attr_setstack(pthread_attr_t *, void *, size_t);
+int		pthread_attr_getdetachstate(const pthread_attr_t * _Nonnull,
+		    int * _Nonnull);
+int		pthread_attr_init(pthread_attr_t * _Nonnull);
+int		pthread_attr_setstacksize(pthread_attr_t * _Nonnull, size_t);
+int		pthread_attr_setguardsize(pthread_attr_t * _Nonnull, size_t);
+int		pthread_attr_setstack(pthread_attr_t * _Nonnull, void *,
+		    size_t);
 int		pthread_attr_setstackaddr(pthread_attr_t *, void *);
-int		pthread_attr_setdetachstate(pthread_attr_t *, int);
-int		pthread_barrier_destroy(pthread_barrier_t *);
-int		pthread_barrier_init(pthread_barrier_t *,
+int		pthread_attr_setdetachstate(pthread_attr_t * _Nonnull, int);
+int		pthread_barrier_destroy(pthread_barrier_t * _Nonnull);
+int		pthread_barrier_init(pthread_barrier_t * _Nonnull,
 			const pthread_barrierattr_t *, unsigned);
-int		pthread_barrier_wait(pthread_barrier_t *);
-int		pthread_barrierattr_destroy(pthread_barrierattr_t *);
-int		pthread_barrierattr_getpshared(const pthread_barrierattr_t *,
-			int *);
-int		pthread_barrierattr_init(pthread_barrierattr_t *);
-int		pthread_barrierattr_setpshared(pthread_barrierattr_t *, int);
+int		pthread_barrier_wait(pthread_barrier_t * _Nonnull);
+int		pthread_barrierattr_destroy(pthread_barrierattr_t * _Nonnull);
+int		pthread_barrierattr_getpshared(
+		    const pthread_barrierattr_t * _Nonnull, int * _Nonnull);
+int		pthread_barrierattr_init(pthread_barrierattr_t * _Nonnull);
+int		pthread_barrierattr_setpshared(pthread_barrierattr_t * _Nonnull,
+		    int);
 
 #define		pthread_cleanup_push(cleanup_routine, cleanup_arg)		\
 		{								\
@@ -183,100 +192,109 @@ int		pthread_barrierattr_setpshared(pthread_barrierattr_t *, int);
 			__pthread_cleanup_pop_imp(execute);			\
 		}
 
-int		pthread_condattr_destroy(pthread_condattr_t *);
-int		pthread_condattr_getclock(const pthread_condattr_t *,
-			clockid_t *);
-int		pthread_condattr_getpshared(const pthread_condattr_t *, int *);
-int		pthread_condattr_init(pthread_condattr_t *);
-int		pthread_condattr_setclock(pthread_condattr_t *, clockid_t);
-int		pthread_condattr_setpshared(pthread_condattr_t *, int);
-int		pthread_cond_broadcast(pthread_cond_t *);
-int		pthread_cond_destroy(pthread_cond_t *);
-int		pthread_cond_init(pthread_cond_t *,
+int		pthread_condattr_destroy(pthread_condattr_t * _Nonnull);
+int		pthread_condattr_getclock(const pthread_condattr_t * _Nonnull,
+		    clockid_t * _Nonnull);
+int		pthread_condattr_getpshared(const pthread_condattr_t * _Nonnull,
+		    int * _Nonnull);
+int		pthread_condattr_init(pthread_condattr_t * _Nonnull);
+int		pthread_condattr_setclock(pthread_condattr_t * _Nonnull,
+		    clockid_t);
+int		pthread_condattr_setpshared(pthread_condattr_t * _Nonnull, int);
+int		pthread_cond_broadcast(pthread_cond_t * _Nonnull);
+int		pthread_cond_destroy(pthread_cond_t * _Nonnull);
+int		pthread_cond_init(pthread_cond_t * _Nonnull,
 			const pthread_condattr_t *);
-int		pthread_cond_signal(pthread_cond_t *);
-int		pthread_cond_timedwait(pthread_cond_t *,
-			pthread_mutex_t *__mutex, const struct timespec *)
+int		pthread_cond_signal(pthread_cond_t * _Nonnull);
+int		pthread_cond_timedwait(pthread_cond_t * _Nonnull,
+		    pthread_mutex_t * _Nonnull __mutex,
+		    const struct timespec * _Nonnull)
 		    __requires_exclusive(*__mutex);
-int		pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *__mutex)
+int		pthread_cond_wait(pthread_cond_t * _Nonnull,
+		    pthread_mutex_t * _Nonnull __mutex)
 		    __requires_exclusive(*__mutex);
-int		pthread_create(pthread_t *, const pthread_attr_t *,
-			void *(*) (void *), void *);
+int		pthread_create(pthread_t * _Nonnull, const pthread_attr_t *,
+		    void *(* _Nonnull) (void *), void *);
 int		pthread_detach(pthread_t);
 int		pthread_equal(pthread_t, pthread_t);
 void		pthread_exit(void *) __dead2;
 void		*pthread_getspecific(pthread_key_t);
-int		pthread_getcpuclockid(pthread_t, clockid_t *);
+int		pthread_getcpuclockid(pthread_t, clockid_t * _Nonnull);
 int		pthread_join(pthread_t, void **);
-int		pthread_key_create(pthread_key_t *,
-			void (*) (void *));
+int		pthread_key_create(pthread_key_t * _Nonnull,
+		    void (*) (void *));
 int		pthread_key_delete(pthread_key_t);
-int		pthread_mutexattr_init(pthread_mutexattr_t *);
-int		pthread_mutexattr_destroy(pthread_mutexattr_t *);
-int		pthread_mutexattr_getpshared(const pthread_mutexattr_t *,
-			int *);
-int		pthread_mutexattr_gettype(pthread_mutexattr_t *, int *);
-int		pthread_mutexattr_settype(pthread_mutexattr_t *, int);
-int		pthread_mutexattr_setpshared(pthread_mutexattr_t *, int);
-int		pthread_mutex_consistent(pthread_mutex_t *__mutex)
-			__nonnull(1) __requires_exclusive(*__mutex);
-int		pthread_mutex_destroy(pthread_mutex_t *__mutex)
+int		pthread_mutexattr_init(pthread_mutexattr_t * _Nonnull);
+int		pthread_mutexattr_destroy(pthread_mutexattr_t * _Nonnull);
+int		pthread_mutexattr_getpshared(
+		    const pthread_mutexattr_t * _Nonnull, int * _Nonnull);
+int		pthread_mutexattr_gettype(pthread_mutexattr_t * _Nonnull,
+		    int * _Nonnull);
+int		pthread_mutexattr_settype(pthread_mutexattr_t * _Nonnull, int);
+int		pthread_mutexattr_setpshared(pthread_mutexattr_t * _Nonnull,
+		    int);
+int		pthread_mutex_consistent(pthread_mutex_t * _Nonnull __mutex)
+		    __requires_exclusive(*__mutex);
+int		pthread_mutex_destroy(pthread_mutex_t * _Nonnull __mutex)
 		    __requires_unlocked(*__mutex);
-int		pthread_mutex_init(pthread_mutex_t *__mutex,
-			const pthread_mutexattr_t *)
+int		pthread_mutex_init(pthread_mutex_t * _Nonnull __mutex,
+		    const pthread_mutexattr_t *)
 		    __requires_unlocked(*__mutex);
-int		pthread_mutex_lock(pthread_mutex_t *__mutex)
-                    __locks_exclusive(*__mutex);
-int		pthread_mutex_trylock(pthread_mutex_t *__mutex)
-                    __trylocks_exclusive(0, *__mutex);
-int		pthread_mutex_timedlock(pthread_mutex_t *__mutex,
-			const struct timespec *)
-                    __trylocks_exclusive(0, *__mutex);
-int		pthread_mutex_unlock(pthread_mutex_t *__mutex)
+int		pthread_mutex_lock(pthread_mutex_t * _Nonnull __mutex)
+		    __locks_exclusive(*__mutex);
+int		pthread_mutex_trylock(pthread_mutex_t * _Nonnull __mutex)
+		    __trylocks_exclusive(0, *__mutex);
+int		pthread_mutex_timedlock(pthread_mutex_t * _Nonnull __mutex,
+		    const struct timespec * _Nonnull)
+		    __trylocks_exclusive(0, *__mutex);
+int		pthread_mutex_unlock(pthread_mutex_t * _Nonnull __mutex)
 		    __unlocks(*__mutex);
-int		pthread_once(pthread_once_t *, void (*) (void));
-int		pthread_rwlock_destroy(pthread_rwlock_t *__rwlock)
+int		pthread_once(pthread_once_t * _Nonnull,
+		    void (* _Nonnull) (void));
+int		pthread_rwlock_destroy(pthread_rwlock_t * _Nonnull __rwlock)
 		    __requires_unlocked(*__rwlock);
-int		pthread_rwlock_init(pthread_rwlock_t *__rwlock,
-			const pthread_rwlockattr_t *)
+int		pthread_rwlock_init(pthread_rwlock_t * _Nonnull __rwlock,
+		    const pthread_rwlockattr_t *)
 		    __requires_unlocked(*__rwlock);
-int		pthread_rwlock_rdlock(pthread_rwlock_t *__rwlock)
-                    __locks_shared(*__rwlock);
-int		pthread_rwlock_timedrdlock(pthread_rwlock_t *__rwlock,
-			const struct timespec *)
-                    __trylocks_shared(0, *__rwlock);
-int		pthread_rwlock_timedwrlock(pthread_rwlock_t *__rwlock,
-			const struct timespec *)
-                    __trylocks_exclusive(0, *__rwlock);
-int		pthread_rwlock_tryrdlock(pthread_rwlock_t *__rwlock)
-                    __trylocks_shared(0, *__rwlock);
-int		pthread_rwlock_trywrlock(pthread_rwlock_t *__rwlock)
-                    __trylocks_exclusive(0, *__rwlock);
-int		pthread_rwlock_unlock(pthread_rwlock_t *__rwlock)
+int		pthread_rwlock_rdlock(pthread_rwlock_t * _Nonnull __rwlock)
+		    __locks_shared(*__rwlock);
+int		pthread_rwlock_timedrdlock(pthread_rwlock_t * _Nonnull __rwlock,
+		    const struct timespec * _Nonnull)
+		    __trylocks_shared(0, *__rwlock);
+int		pthread_rwlock_timedwrlock(pthread_rwlock_t * _Nonnull __rwlock,
+		    const struct timespec * _Nonnull)
+		    __trylocks_exclusive(0, *__rwlock);
+int		pthread_rwlock_tryrdlock(pthread_rwlock_t * _Nonnull __rwlock)
+		    __trylocks_shared(0, *__rwlock);
+int		pthread_rwlock_trywrlock(pthread_rwlock_t * _Nonnull __rwlock)
+		    __trylocks_exclusive(0, *__rwlock);
+int		pthread_rwlock_unlock(pthread_rwlock_t * _Nonnull __rwlock)
 		    __unlocks(*__rwlock);
-int		pthread_rwlock_wrlock(pthread_rwlock_t *__rwlock)
-                    __locks_exclusive(*__rwlock);
-int		pthread_rwlockattr_destroy(pthread_rwlockattr_t *);
-int		pthread_rwlockattr_getkind_np(const pthread_rwlockattr_t *,
-			int *);
-int		pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *,
-			int *);
-int		pthread_rwlockattr_init(pthread_rwlockattr_t *);
-int		pthread_rwlockattr_setkind_np(pthread_rwlockattr_t *, int);
-int		pthread_rwlockattr_setpshared(pthread_rwlockattr_t *, int);
+int		pthread_rwlock_wrlock(pthread_rwlock_t * _Nonnull __rwlock)
+		    __locks_exclusive(*__rwlock);
+int		pthread_rwlockattr_destroy(pthread_rwlockattr_t * _Nonnull);
+int		pthread_rwlockattr_getkind_np(
+		    const pthread_rwlockattr_t * _Nonnull, int *);
+int		pthread_rwlockattr_getpshared(
+		    const pthread_rwlockattr_t * _Nonnull, int * _Nonnull);
+int		pthread_rwlockattr_init(pthread_rwlockattr_t * _Nonnull);
+int		pthread_rwlockattr_setkind_np(pthread_rwlockattr_t * _Nonnull,
+		    int);
+int		pthread_rwlockattr_setpshared(pthread_rwlockattr_t * _Nonnull,
+		    int);
 pthread_t	pthread_self(void);
 int		pthread_setspecific(pthread_key_t, const void *);
 
-int		pthread_spin_init(pthread_spinlock_t *__spin, int)
+int		pthread_spin_init(pthread_spinlock_t * _Nonnull __spin, int)
 		    __requires_unlocked(*__spin);
-int		pthread_spin_destroy(pthread_spinlock_t *__spin)
+int		pthread_spin_destroy(pthread_spinlock_t * _Nonnull __spin)
 		    __requires_unlocked(*__spin);
-int		pthread_spin_lock(pthread_spinlock_t *__spin)
-                    __locks_exclusive(*__spin);
-int		pthread_spin_trylock(pthread_spinlock_t *__spin)
-                    __trylocks_exclusive(0, *__spin);
-int		pthread_spin_unlock(pthread_spinlock_t *__spin)
-		    __unlocks(*__spin);
+int		pthread_spin_lock(pthread_spinlock_t * _Nonnull __spin)
+			__locks_exclusive(*__spin);
+int		pthread_spin_trylock(pthread_spinlock_t * _Nonnull __spin)
+			__trylocks_exclusive(0, *__spin);
+int		pthread_spin_unlock(pthread_spinlock_t * _Nonnull __spin)
+			__unlocks(*__spin);
 int		pthread_cancel(pthread_t);
 int		pthread_setcancelstate(int, int *);
 int		pthread_setcanceltype(int, int *);
@@ -288,35 +306,36 @@ int		pthread_setprio(pthread_t, int);
 void		pthread_yield(void);
 #endif
 
-int		pthread_mutexattr_getprioceiling(pthread_mutexattr_t *,
-			int *);
-int		pthread_mutexattr_setprioceiling(pthread_mutexattr_t *,
-			int);
+int		pthread_mutexattr_getprioceiling(pthread_mutexattr_t *, int *);
+int		pthread_mutexattr_setprioceiling(pthread_mutexattr_t *, int);
 int		pthread_mutex_getprioceiling(pthread_mutex_t *, int *);
 int		pthread_mutex_setprioceiling(pthread_mutex_t *, int, int *);
 
 int		pthread_mutexattr_getprotocol(pthread_mutexattr_t *, int *);
 int		pthread_mutexattr_setprotocol(pthread_mutexattr_t *, int);
 
-int		pthread_mutexattr_getrobust(pthread_mutexattr_t *__restrict,
-			int *__restrict) __nonnull_all;
-int		pthread_mutexattr_setrobust(pthread_mutexattr_t *, int)
-			__nonnull(1);
+int		pthread_mutexattr_getrobust(
+		    pthread_mutexattr_t * _Nonnull __restrict,
+		    int * _Nonnull __restrict);
+int		pthread_mutexattr_setrobust(pthread_mutexattr_t * _Nonnull,
+		    int);
 
 int		pthread_attr_getinheritsched(const pthread_attr_t *, int *);
-int		pthread_attr_getschedparam(const pthread_attr_t *,
-			struct sched_param *);
-int		pthread_attr_getschedpolicy(const pthread_attr_t *, int *);
-int		pthread_attr_getscope(const pthread_attr_t *, int *);
+int		pthread_attr_getschedparam(const pthread_attr_t * _Nonnull,
+		    struct sched_param * _Nonnull);
+int		pthread_attr_getschedpolicy(const pthread_attr_t * _Nonnull,
+		    int * _Nonnull);
+int		pthread_attr_getscope(const pthread_attr_t * _Nonnull,
+		    int * _Nonnull);
 int		pthread_attr_setinheritsched(pthread_attr_t *, int);
-int		pthread_attr_setschedparam(pthread_attr_t *,
-			const struct sched_param *);
-int		pthread_attr_setschedpolicy(pthread_attr_t *, int);
-int		pthread_attr_setscope(pthread_attr_t *, int);
-int		pthread_getschedparam(pthread_t pthread, int *,
-			struct sched_param *);
+int		pthread_attr_setschedparam(pthread_attr_t * _Nonnull,
+		    const struct sched_param * _Nonnull);
+int		pthread_attr_setschedpolicy(pthread_attr_t * _Nonnull, int);
+int		pthread_attr_setscope(pthread_attr_t * _Nonnull, int);
+int		pthread_getschedparam(pthread_t pthread, int * _Nonnull,
+		    struct sched_param * _Nonnull);
 int		pthread_setschedparam(pthread_t, int,
-			const struct sched_param *);
+		    const struct sched_param * _Nonnull);
 #if __XSI_VISIBLE
 int		pthread_getconcurrency(void);
 int		pthread_setconcurrency(int);
@@ -326,5 +345,6 @@ void		__pthread_cleanup_push_imp(void (*)(void *), void *,
 			struct _pthread_cleanup_info *);
 void		__pthread_cleanup_pop_imp(int);
 __END_DECLS
+__NULLABILITY_PRAGMA_POP
 
-#endif
+#endif	/* _PTHREAD_H_ */
diff --git a/include/signal.h b/include/signal.h
index 9d874de..f9b6923 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -41,6 +41,8 @@
 #include <sys/_ucontext.h>
 #endif
 
+__NULLABILITY_PRAGMA_PUSH
+
 #if __BSD_VISIBLE
 /*
  * XXX should enlarge these, if only to give empty names instead of bounds
@@ -82,10 +84,11 @@ int	sigdelset(sigset_t *, int);
 int	sigemptyset(sigset_t *);
 int	sigfillset(sigset_t *);
 int	sigismember(const sigset_t *, int);
-int	sigpending(sigset_t *);
+int	sigpending(sigset_t * _Nonnull);
 int	sigprocmask(int, const sigset_t * __restrict, sigset_t * __restrict);
-int	sigsuspend(const sigset_t *);
-int	sigwait(const sigset_t * __restrict, int * __restrict);
+int	sigsuspend(const sigset_t * _Nonnull);
+int	sigwait(const sigset_t * _Nonnull __restrict,
+	    int * _Nonnull __restrict);
 #endif
 
 #if __POSIX_VISIBLE >= 199506 || __XSI_VISIBLE >= 600
@@ -104,7 +107,7 @@ int	sighold(int);
 int	sigignore(int);
 int	sigpause(int);
 int	sigrelse(int);
-void	(*sigset(int, void (*)(int)))(int);
+void	(* _Nullable sigset(int, void (* _Nullable)(int)))(int);
 int	xsi_sigpause(int);
 #endif
 
@@ -124,5 +127,6 @@ int	sigstack(const struct sigstack *, struct sigstack *);
 int	sigvec(int, struct sigvec *, struct sigvec *);
 #endif
 __END_DECLS
+__NULLABILITY_PRAGMA_POP
 
 #endif /* !_SIGNAL_H_ */
diff --git a/include/stdio.h b/include/stdio.h
index 7b7980e..4c82f90 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -40,6 +40,8 @@
 #include <sys/_null.h>
 #include <sys/_types.h>
 
+__NULLABILITY_PRAGMA_PUSH
+
 typedef	__off_t		fpos_t;
 
 #ifndef _SIZE_T_DECLARED
@@ -123,10 +125,10 @@ struct __sFILE {
 
 	/* operations */
 	void	*_cookie;	/* (*) cookie passed to io functions */
-	int	(*_close)(void *);
-	int	(*_read)(void *, char *, int);
-	fpos_t	(*_seek)(void *, fpos_t, int);
-	int	(*_write)(void *, const char *, int);
+	int	(* _Nullable _close)(void *);
+	int	(* _Nullable _read)(void *, char *, int);
+	fpos_t	(* _Nullable _seek)(void *, fpos_t, int);
+	int	(* _Nullable _write)(void *, const char *, int);
 
 	/* separate buffer for long sequences of ungetc() */
 	struct	__sbuf _ub;	/* ungetc buffer */
@@ -425,10 +427,10 @@ extern const char * const sys_errlist[];
  * Stdio function-access interface.
  */
 FILE	*funopen(const void *,
-	    int (*)(void *, char *, int),
-	    int (*)(void *, const char *, int),
-	    fpos_t (*)(void *, fpos_t, int),
-	    int (*)(void *));
+	    int (* _Nullable)(void *, char *, int),
+	    int (* _Nullable)(void *, const char *, int),
+	    fpos_t (* _Nullable)(void *, fpos_t, int),
+	    int (* _Nullable)(void *));
 #define	fropen(cookie, fn) funopen(cookie, fn, 0, 0, 0)
 #define	fwopen(cookie, fn) funopen(cookie, 0, fn, 0, 0)
 
@@ -541,4 +543,6 @@ extern int __isthreaded;
 #endif /* __cplusplus */
 
 __END_DECLS
+__NULLABILITY_PRAGMA_POP
+
 #endif /* !_STDIO_H_ */
diff --git a/include/stdlib.h b/include/stdlib.h
index 1de702f..26a2775 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -37,6 +37,8 @@
 #include <sys/_null.h>
 #include <sys/_types.h>
 
+__NULLABILITY_PRAGMA_PUSH
+
 #if __BSD_VISIBLE
 #ifndef _RUNE_T_DECLARED
 typedef	__rune_t	rune_t;
@@ -81,12 +83,12 @@ extern int ___mb_cur_max(void);
 
 _Noreturn void	 abort(void);
 int	 abs(int) __pure2;
-int	 atexit(void (*)(void));
+int	 atexit(void (* _Nonnull)(void));
 double	 atof(const char *);
 int	 atoi(const char *);
 long	 atol(const char *);
 void	*bsearch(const void *, const void *, size_t,
-	    size_t, int (*)(const void *, const void *));
+	    size_t, int (*)(const void * _Nonnull, const void *));
 void	*calloc(size_t, size_t) __malloc_like __result_use_check
 	     __alloc_size(1) __alloc_size(2);
 div_t	 div(int, int) __pure2;
@@ -100,7 +102,7 @@ int	 mblen(const char *, size_t);
 size_t	 mbstowcs(wchar_t * __restrict , const char * __restrict, size_t);
 int	 mbtowc(wchar_t * __restrict, const char * __restrict, size_t);
 void	 qsort(void *, size_t, size_t,
-	    int (*)(const void *, const void *));
+	    int (* _Nonnull)(const void *, const void *));
 int	 rand(void);
 void	*realloc(void *, size_t) __result_use_check __alloc_size(2);
 void	 srand(unsigned);
@@ -260,9 +262,9 @@ void	 arc4random_stir(void);
 __uint32_t 
 	 arc4random_uniform(__uint32_t);
 #ifdef __BLOCKS__
-int	 atexit_b(void (^)(void));
+int	 atexit_b(void (^ _Nonnull)(void));
 void	*bsearch_b(const void *, const void *, size_t,
-	    size_t, int (^)(const void *, const void *));
+	    size_t, int (^ _Nonnull)(const void *, const void *));
 #endif
 char	*getbsize(int *, long *);
 					/* getcap(3) functions */
@@ -286,11 +288,13 @@ int	 getloadavg(double [], int);
 const char *
 	 getprogname(void);
 
-int	 heapsort(void *, size_t, size_t, int (*)(const void *, const void *));
+int	 heapsort(void *, size_t, size_t,
+	    int (* _Nonnull)(const void *, const void *));
 #ifdef __BLOCKS__
-int	 heapsort_b(void *, size_t, size_t, int (^)(const void *, const void *));
+int	 heapsort_b(void *, size_t, size_t,
+	    int (^ _Nonnull)(const void *, const void *));
 void	 qsort_b(void *, size_t, size_t,
-	    int (^)(const void *, const void *));
+	    int (^ _Nonnull)(const void *, const void *));
 #endif
 int	 l64a_r(long, char *, int);
 int	 mergesort(void *, size_t, size_t, int (*)(const void *, const void *));
@@ -324,5 +328,6 @@ __uint64_t
 extern char *suboptarg;			/* getsubopt(3) external variable */
 #endif /* __BSD_VISIBLE */
 __END_DECLS
+__NULLABILITY_PRAGMA_POP
 
 #endif /* !_STDLIB_H_ */