[util.smartptr.shared.obs], [util.smartptr.shared.create] use nullptr for null pointer constant

Author: jwakely

source/memory.tex

@@ -3619,7 +3619,7 @@
 \begin{itemdescr}
 \pnum
 \expects
-\tcode{get() != 0}.
+\tcode{get() != nullptr}.
 
 \pnum
 \returns
@@ -3642,7 +3642,7 @@
 \begin{itemdescr}
 \pnum
 \expects
-\tcode{get() != 0}.
+\tcode{get() != nullptr}.
 
 \pnum
 \returns
@@ -3665,7 +3665,7 @@
 \begin{itemdescr}
 \pnum
 \expects
-\tcode{get() != 0 \&\& i >= 0}.
+\tcode{get() != nullptr \&\& i >= 0}.
 If \tcode{T} is \tcode{U[N]}, \tcode{i < N}.
 
 \pnum
@@ -3731,7 +3731,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-\tcode{get() != 0}.
+\tcode{get() != nullptr}.
 \end{itemdescr}
 
 \indexlibrarymember{owner_before}{shared_ptr}%
@@ -3797,7 +3797,7 @@
 
 \pnum
 \ensures
-\tcode{r.get() != 0 \&\& r.use_count() == 1},
+\tcode{r.get() != nullptr \&\& r.use_count() == 1},
 where \tcode{r} is the return value.
 
 \pnum