add flush method

filemanager.h

@@ -141,7 +141,9 @@ class FileManager {
   virtual int write(int8_t fd, const void *buf, int nbyte) = 0;
   virtual int read(int8_t fd, void *buf, int nbyte) = 0;
   virtual int lseek(int8_t fd, int offset, int whence) = 0;
-  
+
+  virtual void flush() = 0;
+
  protected:
   volatile unsigned long fileSeekPositions[MAXFILES];
   char cachedNames[MAXFILES][MAXPATH];

nix/nix-filemanager.cpp

@@ -290,3 +290,8 @@ int NixFileManager::lseek(int8_t fd, int offset, int whence)
   exit(1); // this is an error condition we need to find and fix if it happens
   return -1;
 };
+
+void NixFileManager::flush()
+{
+  // No files are kept open, so there's nothing to flush
+}

nix/nix-filemanager.h

@@ -26,6 +26,7 @@ class NixFileManager : public FileManager {
   virtual int read(int8_t fd, void *buf, int nbyte);
   virtual int lseek(int8_t fd, int offset, int whence);
 
+  virtual void flush();
  private:
   int8_t numCached;
   

teensy/teensy-filemanager.cpp

@@ -300,3 +300,12 @@ int TeensyFileManager::lseek(int8_t fd, int offset, int whence)
   return -1;
 };
 
+void TeensyFileManager::flush()
+{
+  if (cacheFd == -1)
+    return;
+  
+  cacheFile.close();
+  cacheFd = -1;
+}
+

teensy/teensy-filemanager.h

@@ -27,7 +27,9 @@ class TeensyFileManager : public FileManager {
   virtual int write(int8_t fd, const void *buf, int nbyte);
   virtual int read(int8_t fd, void *buf, int nbyte);
   virtual int lseek(int8_t fd, int offset, int whence);
-  
+
+  virtual void flush();
+
  private:
   bool _prepCache(int8_t fd);