current 'print' really does 'println' ... would be nice to support both

Showing the timestamp as a raw ms count can be helpful for doing time-math, but for visual inspection, it can be much easier to have the timestamp formatted as something like [ HH:MM:SS.MMM ]. For more than 100 hours, an extra H digit can be added.

I suggest the addition of a format switch function, something like formatTimestampOn();

It would be nice for the Debug Utils to be orthogonal so that once a debug level is set, functionality in other parts of the code can be enabled or disabled programmatically.

Add int getDebugMessageLevel(void); and int getDebugLevel(void); to Arduino_DebugUtils.h, complimenting the setDebugMessageLevel() and setDebugLevel() functions.

Add

int getDebugMessageLevel(void) {
  return Debug.getDebugLevel();
}

to Arduino_DebugUtils.cpp

There is a compiler warning/error that occurs on build. It is:

...\Arduino_DebugUtils.cpp: In member function 'void Arduino_DebugUtils::print(int, const __FlashStringHelper*, ...)':
...\Arduino_DebugUtils.cpp:86:3: warning: second parameter of 'va_start' not last named argument [-Wvarargs]
va_start(args, fmt_str.c_str());

From my investigation, is seems that line 86 (of "Arduino_DebugUtils.cpp") is:

va_start(args, fmt_str.c_str());

and should instead be:

va_start(args, fmt);

I'm not overly familiar with that macro, but this version does stop the error and seems to function correctly when I run the examples.

The library.properties file is out of date. It was updated Aug 25, 2020. The library was updated Feb 18, 2022 to add add "newlineOn" and "newlineOff" methods. I believe this is preventing the Arduino library manager from updating.

Hi, has there been any discussion around adding individual functions for each debug logging level, instead of passing in the level explicitly, similar to how the logging module in python works? I believe something like this should work:

void Arduino_DebugUtils::info(const char * fmt, ...)
{
  va_list args;
  va_start(args, fmt);
  print(DBG_INFO, fmt, args);
  va_end(args);
}

I would be more than happy to open a PR if this feels like something that should be added

At times, it can be helpful to print the current debug level to the serial monitor as a string. I've implemented this in my own code, but it could be helpful to include in the library to be accessible to all...

// Enum to String Inline Function
//----------------------------------------------------------------------------
  // * Translates enum value to a printable string
  // * enums are mapped to strings by order in list
  // * use static inline keywords to allow function definition in .h file   

 static inline char* debugLevelToString(int debugLevel)
    {
      char* str[] =
      {
        "DBG_NONE",
        "DBG_ERROR",
        "DBG_WARNING",
        "DBG_INFO",
        "DBG_DEBUG",
        "DBG_VERBOSE"
      };

      return str[debugLevel+1];   // DBG_NONE assigned to -1, so add 1 for correct output string
    }

Is there a new release planned that includes the recent introduction of DEBUG_* macros for Debug.print()?

The example:
int i = 1; float pi = 3.1459; Debug.print(DBG_VERBOSE, "i = %d, pi = %f", i, pi);

Results in:
i = 1, pi = ?

It looks like pi=%f doesn't work.

When looking at a wall of debug print statements, it can be useful to see what debug level each statement was printed at so that you can decide if a particular statement should be moved to a different debug level. This could be achieved with as little as a single character, e.g. DBG_ERROR = E, DBG_WARNING = W, etc...

I suggest adding a switch to include printing the debug level of each Debug.print statement, e.g.

showDebugLevelOn()

Debug.print statements could then look like:

[ timestamp ] [E] "rest of print statement..."

or

[ timestamp E ] "rest of print statement..."