Merge #10483: scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL

90d4d89 scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL (practicalswift)

Pull request description:

  Since C++11 the macro `NULL` may be:
  * an integer literal with value zero, or
  * a prvalue of type `std::nullptr_t`

  By using the C++11 keyword `nullptr` we are guaranteed a prvalue of type `std::nullptr_t`.

  For a more thorough discussion, see "A name for the null pointer: nullptr" (Sutter &
  Stroustrup), http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2431.pdf

  With this patch applied there are no `NULL` macro usages left in the repo:

  ```
  $ git grep NULL -- "*.cpp" "*.h" | egrep -v '(/univalue/|/secp256k1/|/leveldb/|_NULL|NULLDUMMY|torcontrol.*NULL|NULL cert)' | wc -l
  0
  ```

  The road towards `nullptr` (C++11) is split into two PRs:
  * `NULL` → `nullptr` is handled in PR #10483 (scripted, this PR)
  * `0` → `nullptr` is handled in PR #10645 (manual)

Tree-SHA512: 3c395d66f2ad724a8e6fed74b93634de8bfc0c0eafac94e64e5194c939499fefd6e68f047de3083ad0b4eff37df9a8a3a76349aa17d55eabbd8e0412f140a297

src/rpc/server.cpp

@@ -30,7 +30,7 @@ static bool fRPCInWarmup = true;
 static std::string rpcWarmupStatus("RPC server started");
 static CCriticalSection cs_rpcWarmup;
 /* Timer-creating functions */
-static RPCTimerInterface* timerInterface = NULL;
+static RPCTimerInterface* timerInterface = nullptr;
 /* Map of name to timer. */
 static std::map<std::string, std::unique_ptr<RPCTimerBase> > deadlineTimers;
 
@@ -291,7 +291,7 @@ const CRPCCommand *CRPCTable::operator[](const std::string &name) const
 {
     std::map<std::string, const CRPCCommand*>::const_iterator it = mapCommands.find(name);
     if (it == mapCommands.end())
-        return NULL;
+        return nullptr;
     return (*it).second;
 }
 
@@ -537,7 +537,7 @@ void RPCSetTimerInterface(RPCTimerInterface *iface)
 void RPCUnsetTimerInterface(RPCTimerInterface *iface)
 {
     if (timerInterface == iface)
-        timerInterface = NULL;
+        timerInterface = nullptr;
 }
 
 void RPCRunLater(const std::string& name, std::function<void(void)> func, int64_t nSeconds)