diff --git a/hprint.cpp b/hprint.cpp
index 6cde00c3..4e14f4ce 100644
--- a/hprint.cpp
+++ b/hprint.cpp
@@ -81,6 +81,7 @@ struct hstream {
   virtual char read_char() = 0;
   virtual void read_chars(char* c, size_t q) { while(q--) *(c++) = read_char(); }
   virtual color_t get_vernum() { return VERNUM_HEX; }
+  virtual void flush() {}
 
   template<class T> void write(const T& t) { hwrite(*this, t); }
   template<class T> void read(T& t) { hread(*this, t); }
@@ -148,6 +149,7 @@ struct fhstream : hstream {
   void write_chars(const char* c, size_t i) override { if(fwrite(c, i, 1, f) != 1) throw hstream_exception(); }
   void read_chars(char* c, size_t i) override { if(fread(c, i, 1, f) != 1) throw hstream_exception(); }
   char read_char() override { char c; read_chars(&c, 1); return c; }
+  virtual void flush() override { fflush(f); }
   };
 
 struct shstream : hstream { 
@@ -263,6 +265,7 @@ struct logger : hstream {
   explicit logger() { doindent = false; }
   void write_char(char c) override;  
   char read_char() override { throw hstream_exception(); }
+  void flush() override { fflush(stdout); }
   };
 
 extern logger hlog;