diff --git a/.gitignore b/.gitignore
index 88882270..c76d9961 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ CTestTestfile.cmake
 CMakeCache.txt
 CMakeFiles
 Makefile
+/run-msbuild.bat
diff --git a/posix.cc b/posix.cc
index b4893cd6..63b37c37 100644
--- a/posix.cc
+++ b/posix.cc
@@ -75,6 +75,8 @@ inline std::size_t convert_rwcount(std::size_t count) { return count; }
 #endif
 }
 
+// Implementations of fmt::BufferedFile
+
 fmt::BufferedFile::~BufferedFile() FMT_NOEXCEPT {
   if (file_ && FMT_SYSTEM(fclose(file_)) != 0)
     fmt::report_system_error(errno, "cannot close file");
@@ -102,6 +104,18 @@ int fmt::BufferedFile::fileno() const {
   return fd;
 }
 
+void fmt::BufferedFile::flush() {
+    if (!file_)
+        return;
+    // FIXME: int result = FMT_SYSTEM(fflush(file_));
+    int result = ::fflush(file_);
+    if (result != 0)
+        throw SystemError(errno, "cannot flush file");
+}
+
+
+// Implementations of fmt::File
+
 fmt::File::File(fmt::StringRef path, int oflag) {
   int mode = S_IRUSR | S_IWUSR;
 #ifdef _WIN32
@@ -226,6 +240,7 @@ fmt::BufferedFile fmt::File::fdopen(const char *mode) {
   return file;
 }
 
+
 long fmt::getpagesize() {
 #ifdef _WIN32
   SYSTEM_INFO si = {};
diff --git a/posix.h b/posix.h
index cce1b1b2..0dcc2960 100644
--- a/posix.h
+++ b/posix.h
@@ -53,7 +53,7 @@
 #ifdef FMT_SYSTEM
 # define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
 #else
-# define FMT_SYSTEM(call) call
+# define FMT_SYSTEM(call) ::call
 # ifdef _WIN32
 // Fix warnings about deprecated symbols.
 #  define FMT_POSIX_CALL(call) ::_##call
@@ -182,31 +182,33 @@ public:
   BufferedFile(fmt::StringRef filename, fmt::StringRef mode);
 
   // Gets whether a file is opened
-  bool is_open() { return file_ != 0; }
+  bool is_open() const FMT_NOEXCEPT { return file_ != 0; }
 
   // Closes the file.
   void close();
 
   // Returns the pointer to a FILE object representing this file.
-  FILE *get() const { return file_; }
-
-  void flush() {
-    if (is_open()) {
-      std::fflush(file_);
-    }
-  }
-
+  FILE *get() const FMT_NOEXCEPT{ return file_; }
+  
+  // Gets the file number of a file
   int fileno() const;
 
-  void write_raw(fmt::StringRef str) {
-    if (is_open()) {
-      std::fwrite(str.c_str(), str.size(), 1, file_);
-    }
+  // Flushes the buffer of a file
+  void flush(); // FIXME: Should be const?
+
+  // Writes raw string without formatting
+  std::size_t write_raw(fmt::StringRef str) {
+    // FIXME: throw exception when failing
+    if (!is_open())
+      return 0;
+    return ::fwrite(str.c_str(), str.size(), 1, file_);
   }
+  // Writes a single charactor without formatting
   void write_raw(char c) {
-    if (is_open()) {
-      std::fputc(c, file_);
-    }
+    // FIXME: throw exception when failing
+    if (!is_open())
+      return;
+    ::fputc(c, file_);
   }
 
   void print(fmt::StringRef format_str, const ArgList &args) {