diff --git a/ulog_cpp/messages.cpp b/ulog_cpp/messages.cpp
index 776b5f0..c5c82fd 100644
--- a/ulog_cpp/messages.cpp
+++ b/ulog_cpp/messages.cpp
@@ -278,7 +278,7 @@ Value::NativeTypeVariant Value::asNativeTypeVariant() const
         if (_backing_ref_end - string_start_iterator < _field_ref.arrayLength()) {
           throw AccessException("Decoding fault, memory too short");
         }
-        int string_length = strnlen(string_start_iterator.base(), _field_ref.arrayLength());
+        const int string_length = strnlen(&(*string_start_iterator), _field_ref.arrayLength());
         return std::string(string_start_iterator, string_start_iterator + string_length);
       }
 
diff --git a/ulog_cpp/simple_writer.cpp b/ulog_cpp/simple_writer.cpp
index 0651859..5331147 100644
--- a/ulog_cpp/simple_writer.cpp
+++ b/ulog_cpp/simple_writer.cpp
@@ -5,7 +5,8 @@
 
 #include "simple_writer.hpp"
 
-#ifdef WINDOWS
+#ifdef _WIN32
+#include <windows.h> // NOLINT
 #include <fileapi.h>
 #else
 #include <unistd.h>
@@ -112,8 +113,8 @@ void SimpleWriter::fsync()
 {
   if (_file) {
     fflush(_file);
-#ifdef WINDOWS
-    FlushFileBuffers(static_cast<HANDLE>(_fileno(_file)));
+#ifdef _WIN32
+    FlushFileBuffers(reinterpret_cast<HANDLE>(static_cast<uintptr_t>(_fileno(_file))));
 #else
     ::fsync(fileno(_file));
 #endif