``NULL is a specific instance of a null pointer constant; the generic is

a "null pointer".''

Making good use of the excellent explanations sent to me by Ruslan
Ermilov, Garrett Wollman and Bruce Evans, correct the descriptions of
null pointers.  They are just "null pointers", not nil, not NULL or
".Dv NULL".

Suggested by:	ru, wollman, bde
Reviewed by:	ru, wollman
Pointy hat:	keramida

lib/libc/sys/acct.2

@@ -51,9 +51,7 @@ system call enables or disables the collection of system accounting
 records.
 If the argument
 .Fa file
-is a
-.Dv NULL
-pointer, accounting is disabled.
+is a null pointer, accounting is disabled.
 If
 .Fa file
 is an

lib/libc/sys/adjtime.2

@@ -72,9 +72,7 @@ may not be finished when
 is called again.
 If
 .Fa olddelta
-is not a
-.Dv NULL
-pointer,
+is not a null pointer,
 the structure pointed to will contain, upon return, the
 number of microseconds still to be corrected
 from the earlier call.

lib/libc/sys/aio_suspend.2

@@ -52,18 +52,14 @@ is an array of
 .Fa niocb
 pointers to asynchronous I/O requests.
 Array members containing
-NULL will be silently ignored.
+null pointers will be silently ignored.
 .Pp
 If
 .Fa timeout
-is not a
-.Dv NULL
-pointer, it specifies a maximum interval to suspend.
+is not a null pointer, it specifies a maximum interval to suspend.
 If
 .Fa timeout
-is a
-.Dv NULL
-pointer, the suspend blocks indefinitely.
+is a null pointer, the suspend blocks indefinitely.
 To effect a
 poll, the
 .Fa timeout

lib/libc/sys/getitimer.2

@@ -66,9 +66,7 @@ system call sets a timer to the specified
 .Fa value
 (returning the previous value of the timer if
 .Fa ovalue
-is not a
-.Dv NULL
-pointer).
+is not a null pointer).
 .Pp
 A timer value is defined by the
 .Fa itimerval

lib/libc/sys/recv.2

@@ -63,8 +63,7 @@ it is connection-oriented.
 .Pp
 If
 .Fa from
-is not
-.Dv NULL ,
+is not a null pointer
 and the socket is not connection-oriented,
 the source address of the message is filled in.
 The
@@ -85,7 +84,7 @@ socket (see
 and is identical to
 .Fn recvfrom
 with a
-.Dv NULL
+null pointer passed as its
 .Fa from
 argument.
 As it is redundant, it may not be supported in future releases.

lib/libc/sys/select.2

@@ -108,23 +108,18 @@ to the maximum number of descriptors supported by the system.
 .Pp
 If
 .Fa timeout
-is not a
-.Dv NULL
-pointer, it specifies the maximum interval to wait for the
+is not a null pointer, it specifies the maximum interval to wait for the
 selection to complete.
 System activity can lengthen the interval by
 an indeterminate amount.
 .Pp
 If
 .Fa timeout
-is a
-.Dv NULL
-pointer, the select blocks indefinitely.
+is a null pointer, the select blocks indefinitely.
 .Pp
 To effect a poll, the
 .Fa timeout
-argument should not be
-.Dv NULL ,
+argument should not be a null pointer,
 but it should point to a zero-valued timeval structure.
 .Pp
 Any of
@@ -132,9 +127,7 @@ Any of
 .Fa writefds ,
 and
 .Fa exceptfds
-may be given as
-.Dv NULL
-pointers if no descriptors are of interest.
+may be given as null pointers if no descriptors are of interest.
 .Sh RETURN VALUES
 The
 .Fn select