PIO doesn't build Teensy Floating point support?

Development Platforms
1

I’m using Teensy’s Serial.printf functionality (Teensy 3.2). When I build using the Arduino IDE, everything works fine. When I build using PIO (in Atom), floating point support disappears.

Minimal repro:

void setup() {
  // put your setup code here, to run once:
  Serial.printf("'%s' - This is a string.\n", "Hello world");
  Serial.printf("'%d' - This is an integer.\n", 12345);
  Serial.printf("'%.2f' - This is a float.\n", 1234.56);
  Serial.printf("'%.2f' - This is a rounded float.\n", 1234.56789);
}

void loop() {
  // put your main code here, to run repeatedly:
}

Built from Arduino, this outputs the following:

'Hello world' - This is a string.
'12345' - This is an integer.
'1234.56' - This is a float.
'1234.57' - This is a rounded float.

Built from PlatformIO, it outputs the following:

'Hello world' - This is a string.
'12345' - This is an integer.
'' - This is a float.
'' - This is a rounded float.

Has anyone seen this before? Is there some way to make it work with PIO?

2

Add this somewhere in your sketch:

  // this is the magic trick for printf to support float
  asm(".global _printf_float");

And this if you need scanf to support float:

  // this is the magic trick for scanf to support float
   asm(".global _scanf_float");
1 Like
3

fantastic!! For my own future reference, is this magic trick documented anywhere? And is this magic trick specific to Teensy? Or Specific to PIO, or specific to something else?

4

I had the same problem and asked over on the Teensy forums a while back.

Not sure why it works in Arduino but not via platformio for you. My memory was that it was necessary to add those lines in both environments.

5

This is a bug and was fixed in

The final release is coming soon.