diff --git a/binding.gyp b/binding.gyp
index 54f2568..303ea50 100644
--- a/binding.gyp
+++ b/binding.gyp
@@ -3,7 +3,7 @@
     {
       "target_name": "worker",
       "include_dirs": ["<!(node -e \"require('nan')\")"],
-      "cflags": ["-Wall", "-O2"],
+      "cflags": ["-Wall", "-Wextra", "-O2"],
       "sources": ["src/worker.cc", "src/pow.cc"],
       "conditions": [
         ["OS=='win'", {
diff --git a/src/pow.h b/src/pow.h
index 78fc665..06a59d1 100644
--- a/src/pow.h
+++ b/src/pow.h
@@ -1,5 +1,5 @@
-#ifndef BITMESSAGE_POW_H
-#define BITMESSAGE_POW_H
+#ifndef BITCHAN_BITMESSAGE_POW_H_
+#define BITCHAN_BITMESSAGE_POW_H_
 
 static const int MAX_POOL_SIZE = 1024;
 static const int HASH_SIZE = 64;
@@ -10,4 +10,4 @@ int pow(size_t pool_size,
         uint64_t max_nonce,
         uint64_t* nonce);
 
-#endif
+#endif  // BITCHAN_BITMESSAGE_POW_H_
diff --git a/src/worker.cc b/src/worker.cc
index 01bfb26..cafcc8a 100644
--- a/src/worker.cc
+++ b/src/worker.cc
@@ -10,7 +10,7 @@ using v8::Function;
 using v8::Value;
 using v8::Object;
 using v8::String;
-using v8::Integer;
+using v8::Number;
 
 static const uint64_t MAX_SAFE_INTEGER = 9007199254740991ULL;
 
@@ -51,7 +51,7 @@ class PowWorker : public NanAsyncWorker {
       }
       callback->Call(1, argv);
     } else {
-      Local<Value> argv[] = {NanNull(), NanNew<Integer>(nonce)};
+      Local<Value> argv[] = {NanNull(), NanNew<Number>(nonce)};
       callback->Call(2, argv);
     }
   }