text: ///////////////////////////////////////////////////////////////////////////////
  // \author (c) Marco Paland (info@paland.com)
  //             2014-2019, PALANDesign Hannover, Germany
  //
  // \license The MIT License (MIT)
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  // 
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  // \brief Tiny printf, sprintf and snprintf implementation, optimized for speed on
  //        embedded systems with a very limited resources.
  //        Use this instead of bloated standard/newlib printf.
  //        These routines are thread safe and reentrant.
  //
  ///////////////////////////////////////////////////////////////////////////////
  
  #ifndef _PRINTF_H_
  #define _PRINTF_H_
  
  #include <stdarg.h>
  #include <stddef.h>
  
  
  // Links our mini_uart device to printf
  void _putchar(char);
  
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  /**
   * Tiny printf implementation
   * You have to implement _putchar if you use printf()
   * To avoid conflicts with the regular printf() API it is overridden by macro defines
   * and internal underscore-appended functions like printf_() are used
   * \param format A string that specifies the format of the output
   * \return The number of characters that are written into the array, not counting the terminating null character
   */
  #define printf printf_
  int printf_(const char* format, ...);
  
  
  /**
   * Tiny sprintf implementation
   * Due to security reasons (buffer overflow) YOU SHOULD CONSIDER USING (V)SNPRINTF INSTEAD!
   * \param buffer A pointer to the buffer where to store the formatted string. MUST be big enough to store the output!
   * \param format A string that specifies the format of the output
   * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
   */
  #define sprintf sprintf_
  int sprintf_(char* buffer, const char* format, ...);
  
  
  /**
   * Tiny snprintf/vsnprintf implementation
   * \param buffer A pointer to the buffer where to store the formatted string
   * \param count The maximum number of characters to store in the buffer, including a terminating null character
   * \param format A string that specifies the format of the output
   * \param va A value identifying a variable arguments list
   * \return The number of characters that COULD have been written into the buffer, not counting the terminating
   *         null character. A value equal or larger than count indicates truncation. Only when the returned value
   *         is non-negative and less than count, the string has been completely written.
   */
  #define snprintf  snprintf_
  #define vsnprintf vsnprintf_
  int  snprintf_(char* buffer, size_t count, const char* format, ...);
  int vsnprintf_(char* buffer, size_t count, const char* format, va_list va);
  
  
  /**
   * Tiny vprintf implementation
   * \param format A string that specifies the format of the output
   * \param va A value identifying a variable arguments list
   * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
   */
  #define vprintf vprintf_
  int vprintf_(const char* format, va_list va);
  
  
  /**
   * printf with output function
   * You may use this as dynamic alternative to printf() with its fixed _putchar() output
   * \param out An output function which takes one character and an argument pointer
   * \param arg An argument pointer for user data passed to output function
   * \param format A string that specifies the format of the output
   * \return The number of characters that are sent to the output function, not counting the terminating null character
   */
  int fctprintf(void (*out)(char character, void* arg), void* arg, const char* format, ...);
  
  
  #ifdef __cplusplus
  }
  #endif
  
  
  #endif  // _PRINTF_H_
  