CODEWITHSUNDEEP
c++loggingembedded
DikobrAz
DikobrAz

Reputation: 3737

Minimal conditional logging for C++

I'm working on embedded project and it is very convenient to log information in your code for debugging purposes, but fully blown C++ logger libraries are hardly usable in embedded environment. Can you suggest how to implement simple, clean and fast logging module? I don't really need fine control over logging backends, outputs, levels etc. I just want to enable and disable logging statements without obscuring the code. Currently I'm doing it this way:

#define DEBUG_ENCODER_PRINTF

// ...

#ifdef DEBUG_ENCODER_PRINTF
    debug_printf("enc: %d %d\r\n",
                 get_encoder_unwrapped(0),
                 get_encoder_unwrapped(1));
#endif

But I already have dozens of different logging statements, and a lot of preprocessor definitions make code look ugly.

Upvotes: 2

Views: 781

Answers (2)

DikobrAz
DikobrAz

Reputation: 3737

I did it like this in the end:

#define DEBUG_PRINTF_ENABLED
#define DEBUG_SONAR_PRINTF       false
#define DEBUG_ENCODER_PRINTF     true
// ... 

#ifdef DEBUG_PRINTF_ENABLED
#   define DEBUG_PRINTF(logger, pFormat, ...)\
    { if (DEBUG_##logger##_PRINTF) debug_printf(pFormat, __VA_ARGS__); }
#else
#   define DEBUG_PRINTF(...)
#endif

// ...

DEBUG_PRINTF(ENCODER,
             "enc: %d %d\r\n",
             get_encoder_unwrapped(0),
             get_encoder_unwrapped(1));

Upvotes: 3

Stack Exchange Broke The Law
Stack Exchange Broke The Law

Reputation: 58929

You can eliminate those pesky #ifdefs and #endifs if you do something like this:

#ifdef DEBUG_ENCODER_PRINTF
    #define debug_encoder_printf debug_printf
#else
    #define debug_encoder_printf(...)
#endif

debug_encoder_printf("hi") will now call debug_printf when DEBUG_ENCODER_PRINTF is defined, but if that is not defined, the whole "call" will be removed by the preprocessor (replaced with nothing).

Upvotes: 5

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