Feature request / core lib / Serial.print

alan9988 · January 12, 2022, 1:26am

It would be great if Serial.print and its cousins accepted an argument of type String. String is a special Arduino class, and we work with it often, and thus we sometimes write code like

Serial.println(myStringObj).

This compiles and then crashes during runtime. It would be nice if either a) it didn't compile, or b) it ran in the obvious way (using the object's c_str() method).

Thanks for your time!

in0 · January 12, 2022, 2:15am

Hi @alan9988. They do:

github.com

arduino/ArduinoCore-API/blob/1.3.1/api/Print.h#L64


      
          virtual size_t write(const uint8_t *buffer, size_t size);
          size_t write(const char *buffer, size_t size) {
            return write((const uint8_t *)buffer, size);
          }
          
          
// default to zero, meaning "a single write may block"
          // should be overriden by subclasses with buffering
          virtual int availableForWrite() { return 0; }
          
          
size_t print(const __FlashStringHelper *);
          size_t print(const String &);
          size_t print(const char[]);
          size_t print(char);
          size_t print(unsigned char, int = DEC);
          size_t print(int, int = DEC);
          size_t print(unsigned int, int = DEC);
          size_t print(long, int = DEC);
          size_t print(unsigned long, int = DEC);
          size_t print(long long, int = DEC);
          size_t print(unsigned long long, int = DEC);
          size_t print(double, int = 2);

You can see a demonstration of it in the official documentation here:

Thousands of people print String objects every day without problems, so this is definitely unusual. That said, there are definitely ways you can get into trouble using the String class, and in fact some here recommend against its use.

We can probably help you out with your problem, but we'll need you to provide a minimal demonstration sketch we can use to reproduce the issue. We also need to know which board you are using.

alan9988 · January 12, 2022, 4:50am

Seems I was marvelously confused. Thanks for the quick reply, I'll show myself out...

in0 · January 12, 2022, 5:20am

You're welcome. I'm glad if I was able to be of assistance. Enjoy!

system · July 11, 2022, 5:21am

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