diff --git a/code/DefaultIOStream.cpp b/code/DefaultIOStream.cpp
index d10c303d8..e9da3ff70 100644
--- a/code/DefaultIOStream.cpp
+++ b/code/DefaultIOStream.cpp
@@ -110,7 +110,7 @@ size_t DefaultIOStream::FileSize() const
         return 0;
     }
 
-    if (SIZE_MAX == cachedSize) {
+    if (SIZE_MAX == mCachedSize ) {
 
         // Although fseek/ftell would allow us to reuse the existing file handle here,
         // it is generally unsafe because:
@@ -125,18 +125,19 @@ size_t DefaultIOStream::FileSize() const
         int err = _stat64(  mFilename.c_str(), &fileStat );
         if (0 != err)
             return 0;
-        cachedSize = (size_t) (fileStat.st_size);
+        mCachedSize = (size_t) (fileStat.st_size);
 #elif defined __gnu_linux__ || defined __APPLE__ || defined __MACH__
         struct stat fileStat;
         int err = stat(mFilename.c_str(), &fileStat );
         if (0 != err)
             return 0;
-        cachedSize = (size_t) (fileStat.st_size);
+        const unsigned long long cachedSize = fileStat.st_size;
+        mCachedSize = static_cast< size_t >( cachedSize );
 #else
 #   error "Unknown platform"
 #endif
     }
-    return cachedSize;
+    return mCachedSize;
 }
 
 // ----------------------------------------------------------------------------------
diff --git a/code/DefaultIOStream.h b/code/DefaultIOStream.h
index 779858839..83bd3a9d4 100644
--- a/code/DefaultIOStream.h
+++ b/code/DefaultIOStream.h
@@ -111,7 +111,7 @@ private:
     std::string mFilename;
 
     // Cached file size
-    mutable size_t cachedSize;
+    mutable size_t mCachedSize;
 };
 
 
@@ -119,7 +119,7 @@ private:
 inline DefaultIOStream::DefaultIOStream () :
     mFile       (NULL),
     mFilename   (""),
-    cachedSize  (SIZE_MAX)
+    mCachedSize(SIZE_MAX)
 {
     // empty
 }
@@ -130,7 +130,7 @@ inline DefaultIOStream::DefaultIOStream (FILE* pFile,
         const std::string &strFilename) :
     mFile(pFile),
     mFilename(strFilename),
-    cachedSize  (SIZE_MAX)
+    mCachedSize(SIZE_MAX)
 {
     // empty
 }