more improvements:

1. New optional flag to redirect print to stderr. THis can be useful on
host environemtns (e.g linux)
2. non-buffered mode if this flag is true: the preamble msut be printed
manually
2. Getter function for preamble for that case.
3. printChar function: specify whether to print to stderr or stdout

serviceinterface/ServiceInterfaceBuffer.h

@@ -3,43 +3,64 @@
 
 #include <iostream>
 #include <sstream>
-#include <cstdio>
 #include <iomanip>
 
 #ifndef UT699
+
+/**
+ * @brief 	This is the underlying stream buffer which implements the
+ * 			streambuf class and overloads the overflow() and sync() methods
+ * @details
+ * This class is used to modify the output of the stream, for example by adding.
+ * It also calls the char printing function which is implemented in the
+ * board supply package (BSP).
+ */
 class ServiceInterfaceBuffer:
-        public std::basic_streambuf<char,std::char_traits<char>> {
+        public std::streambuf {
 	friend class ServiceInterfaceStream;
 public:
-	ServiceInterfaceBuffer(std::string set_message, uint16_t port,
-			bool addCrToPreamble);
+	ServiceInterfaceBuffer(std::string setMessage, bool errStream,
+			bool addCrToPreamble, uint16_t port);
+
 protected:
 	bool isActive;
-	// This is called when buffer becomes full. If
-	// buffer is not used, then this is called every
-	// time when characters are put to stream.
+	//! This is called when buffer becomes full. If
+	//! buffer is not used, then this is called every
+	//! time when characters are put to stream.
 	int overflow(int c = Traits::eof()) override;
 
-	// This function is called when stream is flushed,
-	// for example when std::endl is put to stream.
+	//! This function is called when stream is flushed,
+	//! for example when std::endl is put to stream.
 	int sync(void) override;
 
 private:
-	// For additional message information
-	std::string log_message;
+	//! For additional message information
+	std::string logMessage;
 	// For EOF detection
 	typedef std::char_traits<char> Traits;
-	// This is useful for some terminal programs which do not have
-	// implicit carriage return with newline characters.
+	//! This is useful for some terminal programs which do not have
+	//! implicit carriage return with newline characters.
 	bool addCrToPreamble;
+	//! This specifies to print to stderr and work in unbuffered mode.
+	bool errStream;
 
 	// Work in buffer mode. It is also possible to work without buffer.
 	static size_t const BUF_SIZE = 128;
 	char buf[BUF_SIZE];
 
-	// In this function, the characters are parsed.
+	//! In this function, the characters are parsed.
 	void putChars(char const* begin, char const* end);
 
+	std::string getPreamble();
+
+	/**
+	 * This helper function returns the zero padded string version of a number.
+	 * The type is deduced automatically.
+	 * @tparam T
+	 * @param num
+	 * @param width
+	 * @return
+	 */
 	template<typename T>
 	std::string zero_padded(const T& num, uint8_t width) {
 	    std::ostringstream string_to_pad;
@@ -52,6 +73,7 @@ private:
 	    return result;
 	}
 };
+
 #endif