As in many similar debugging frameworks, the Rdebug library defines different debug levels. Turn the serial monitor debugging output On and Off with a simple #define.
The heart of the library is the hierarchy. Set the log level to WARN, then the lower groups are also included. In this case, it enables ON, DEBUG, and INFO.
ON < DEBUG < INFO < WARN < ERROR
Set the level to the highest level, i.e., ERROR during development, and reduce it once the code is released.
If the level is OFF, then all debug macros are disabled, and only the usual Arduino serial print statement emits any text to the user.
If the level is ON, a.k.a. lazy mode, you can use the debug and the debugln macros to save you from typing in Serial.print and Serial.println all the time. The macro expands to the latter two functions.
The library includes the following defined levels:
DEBUGLEVEL_OFF - all debug macros are disabled
DEBUGLEVEL_ON - the non-traced macro (lazy mode) is enabled
DEBUGLEVEL_DEBUG - traced debug messages
DEBUGLEVEL_INFO - traced information messages
DEBUGLEVEL_WARN - traced warning messages
DEBUGLEVEL_ERROR - traced error messages
The latter four are identical and produce a slightly different monitor output. You, as the user, decide how to apply these in the code such that it makes sense. They all have the following generic form.
[level][function name:line number] "string message"
The traced macros end with D, I, W, and E for their log level.
debugD(), debuglnD() // DEBUGLEVEL_DEBUG
debugI(), debuglnI() // DEBUGLEVEL_INFO
debugW(), debuglnW() // DEBUGLEVEL_WARN
debugE(), debuglnE() // DEBUGLEVEL_ERROR
The lazy non-trace macro does not have these letters at the end.
debug() ---> Serial.print() // DEBUGLEVEL_ON
debugln() ---> Serial.println() // DEBUGLEVEL_ON
Initially, in your sketch, set the debugging level to DEBUGLEVEL_ERROR so that all debugging messages appear:
#define DEBUGLEVEL_ERROR
Then include the header file:
#include <Rdebug.h>
Experiment with different debug levels to include or exclude the above debug statements with the sketch Rdebug.ino in the examples folder.
Thanks to Ralph S Bacon for his enjoyable YT channel with many valuable tips and hints related to microcontrollers, coding, and everything related to the Arduino echo system.
Ralph's repository and his original debugging implementation.
If you focus on tracing and trying to figure out where your code crashed, look at ArduinoTrace, but it all depends on the objective and how severe the problem is.