text: #ifndef __debug_h
  #define __debug_h
  
  #include <stdio.h>
  #include <errno.h>
  #include <string.h>
  
  #define trace(M, ...) fprintf(stderr, "\tTRACE %s:%d: " M "\n", __FILE__, __LINE__, ##__VA_ARGS__)
  #ifdef NDEBUG
  #define debug(M, ...)
  #else
  #define trace(M, ...) fprintf(stderr, "\tTRACE %s:%d: " M "\n", __FILE__, __LINE__, ##__VA_ARGS__)
  
  #endif
  #endif
  