What does malloc() do in an STM32 MCU run without an OS ?

[Shiina]

How does STM32 dynamically allocate memory ?

[Andrew Neil · Accepted solution]

https://stackoverflow.com/questions/77829982/how-does-arm-none-eabi-gcc-9-2-implement-malloc-free

EDIT

You didn't state what compiler you're asking about.

The above relates to the GCC/ARM compiler, as used in the STM32CubeIDE, using the newlib library.

Other compilers & libraries are available; eg,

https://developer.arm.com/documentation/dui0067/d/the-c-and-c---libraries/tailoring-storage-management/support-for-malloc

[Tesla DeLorean]

It allocates memory from the heap. In the GNU/GCC sense this is from the top of the statics to the bottom of the stack via sbrk().

On Keil/IAR it would be a section of heap memory of defined size that the linker places after the statics. 

[SofLit]

From the title I understand: in which situation the dynamic allocation is used if no rtos is used, but in the text I understand something else. Need to be concise.

[Shiina]

thanks