simple_writer: add Windows support for fsync

README.md

@@ -4,7 +4,7 @@ Streamed C++ [ULog](https://docs.px4.io/main/en/dev_log/ulog_file_format.html) r
 
 ## Properties
 - Options for keeping log data in memory or processing immediately.
-- Pure C++17 without additional dependencies (`SimpleWriter` requires POSIX for file IO).
+- Pure C++17 without additional dependencies (`SimpleWriter` requires platform-specific `fsync`/`FlushFileBuffers`).
 - The reader is ~10 times as fast compared to the [python implementation](https://github.com/PX4/pyulog).
   However, the API is more low-level, and if you're just looking for an easy-to-use parsing library, use pyulog.
 - Unsupported ULog features:

ulog_cpp/simple_writer.cpp

@@ -5,7 +5,11 @@
 
 #include "simple_writer.hpp"
 
+#ifdef WINDOWS
+#include <fileapi.h>
+#else
 #include <unistd.h>
+#endif
 
 namespace ulog_cpp {
 
@@ -108,7 +112,11 @@ void SimpleWriter::fsync()
 {
   if (_file) {
     fflush(_file);
+#ifdef WINDOWS
+    FlushFileBuffers(static_cast<HANDLE>(_fileno(_file)));
+#else
     ::fsync(fileno(_file));
+#endif
   }
 }
 uint16_t SimpleWriter::writeAddLoggedMessage(const std::string& message_format_name,