u_printf_float - where to set for C_Linker in STM32CubeIDE?

[MFend]

When I compile, I get the following error:

The float formatting support (-u_printf_float)is not enabled from linker flags

I can't find Linker flags/Options/Settings for C - just for MCU G++ Linker. When I chose the option, it still didn't remove the error. It compiles, though and can be run.

[Gpeti]

Just to clarify:

1) I made a mistake, it seems like newlib-nano does support float printf

2) the problem comes from the stack initialisation bug

This issue is discussed many times on different forums on the web but it's a bit confusing.

[kurta999]

I suggest to using this library instead of this linker option.

https://github.com/mpaland/printf

Try to use built-in pritf with RTOS, SWO tracing & floating point support. Good luck :D.

[MFend]

but the _estack pointer is fine in the .ld file...

I saw all of the threads - but they don't seem relevant

/* Highest address of the user mode stack */

_estack = 0x20020000;  /* end of 128K RAM */

[MFend]

The Problems tab is very convenient to see all bugs concentrated into a nice neat list...

[MFend]

Are there any other directions for using this library? What settings do i need to set in the IDE?

[Gpeti]

If it is reliable I agree. But apparently it does not correspond to errors or warnings found by the build system.

[Gpeti]

If you are trying to print on SWV console I cannot help you since I was never able to make it work (on TrueStudio on STM32L4 few months ago I gave up, on STM32CubeIDE and STM32H7 there is a different issue for which I started a dedicated thread).

If you are trying to print in a UART console (via virtual com port or physical RS232), I think the only setup at IDE level is this "float printf" option, and apart from that implement __io_putchar or _write fucntion and configure UART, you can easily find how to do on the web.

[Yuk117 · Accepted solution]

This problem is fixed in STM32CubeIDE ver.1.0.2.

Workaround in older version is to add "-u _printf_float" to MCU GCC Linker -> Miscellaneous -> Other flags.

​

[MFend]

This worked.

thanks...

I'm going to update to the latest release...

[PVaaz.1]

Hello @MFend​ 

are you able to fix it? Is it working for you now?