STM32CubeMX sprintf does not work with float

[ebclr]

I have those 2 similar routines, one to write an integer to the LCD and the other to write a float,  the integer ones work perfectly but the very similar one for float does not work, I'm guessing that sprintf fails for a float on stm32cubemx compiler, any tips on that?

void writeInteger(LiquidCrystal *lcd, int valueToBedisplayed, uint8_t MaxLenghtOfDigitis)
{
   char StringValue[MaxLenghtOfDigitis];
   sprintf(StringValue, "%d", valueToBedisplayed );
   size_t Lengh = strlen(StringValue);
   for (uint8_t i = 0; i < Lengh; i++){
      write(lcd ,*(StringValue+i));
   }
}



void writefloat(LiquidCrystal *lcd, float floatToBeDisplayed, uint8_t MaxLenghtOfDigitis)
{
   char StringValue[MaxLenghtOfDigitis+2];
   sprintf(StringValue, "%f", floatToBeDisplayed );
   size_t Lengh = strlen(StringValue);
   for (uint8_t i = 0; i < Lengh; i++){
      write(lcd ,*(StringValue+i));
   }

[langwadt]

mcu settings:  -u _printf_float

[peter-h]

Have a read around here
https://www.eevblog.com/forum/microcontrollers/is-st-cube-ide-a-piece-of-buggy-crap/msg4363183/#msg4363183

You can have lots of fun with the Newlib libc.a library and it's duff mutexes, its use of the heap, etc

In the end I replaced it with an open source one - all in the thread and here
https://www.eevblog.com/forum/programming/best-thread-safe-printf-and-why-does-printf-need-the-heap-for-f-etc/msg4325479/#msg4325479

[DavidAlfa]

I remember some option in the compiler/linker whatever settings to enable floats in printf

[DavidAlfa]

As I said, here it is

[peter-h]

That gives you the crappy Newlib library from 1990 which uses empty mutex function stubs, and the heap (which also has empty mutex function stubs)

Best to follow the instructions I posted and replace the printf family entirely.

But if not using an RTOS and the program is just simple, it doesn't matter. You do need to set up a heap though (_sbrk etc).