More fixups for orb_advert_t changed to void *

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/uORB/uORBDevices_posix.cpp

@@ -284,7 +284,7 @@ uORB::DeviceNode::publish(const orb_metadata *meta, orb_advert_t handle, const v
 {
   //warnx("uORB::DeviceNode::publish meta = %p", meta);
 
-  if (handle == 0) {
+  if (handle == nullptr) {
     warnx("uORB::DeviceNode::publish called with invalid handle");
     errno = EINVAL;
     return ERROR;

src/modules/uORB/uORBManager_nuttx.cpp

@@ -89,18 +89,18 @@ orb_advert_t uORB::Manager::orb_advertise_multi(const struct orb_metadata *meta,
   /* open the node as an advertiser */
   fd = node_open(PUBSUB, meta, data, true, instance, priority);
   if (fd == ERROR)
-    return 0;
+    return nullptr;
 
   /* get the advertiser handle and close the node */
   result = ioctl(fd, ORBIOCGADVERTISER, (unsigned long)&advertiser);
   close(fd);
   if (result == ERROR)
-    return 0;
+    return nullptr;
 
   /* the advertiser must perform an initial publish to initialise the object */
   result = orb_publish(meta, advertiser, data);
   if (result == ERROR)
-    return 0;
+    return nullptr;
 
   return advertiser;
 }

src/modules/uORB/uORBTest_UnitTest.cpp

@@ -144,7 +144,7 @@ int uORBTest::UnitTest::test()
   t.val = 0;
   ptopic = orb_advertise(ORB_ID(orb_test), &t);
 
-  if (ptopic == 0)
+  if (ptopic == nullptr)
     return test_fail("advertise failed: %d", errno);
 
   test_note("publish handle 0x%08x", ptopic);