Could I know whether freeRTOS is run time configurable?


Could I know whether freeRTOS is run time configurable?

Thanking you.

What exactly do you want to configure at runtime ?

Thanks for the reply. I wish to configure tasks, stacks, semaphores, message queues, memory partitions, and timers.

Sorry - I still don’t really get it.
Basically code related features are compile-time configurable to optimize the footprint of an application as documented FreeRTOS - The Free RTOS configuration constants and configuration options - FREE Open Source RTOS for small real time embedded systems.
Tasks and other supported (enabled and compiled-in) resources are created at runtime.

Thank you. But, it is mentioned in the document uc/OS III, supports run time configuration.

Thanking you.


like @hs2 , I am unclear about what you actually wish to configure at run time instead of build time, so let me take a guess:

In AMX, you had a choice to define your tasks/ parameters (stack size etc) either at run time via a create() function or via a configuration file. That file would actually be translated into a C file used by the OS startup code which would end up in a series of calls to createTask(). That scheme gave you the option to sort of compile-time configure your system.

FreeRTOS does not know rhat concept, although some eco systems provide wrappers for that kind of thing. In “pure” FreeRTOS, everything is run time configured by default.

Does that answer your question?

Hi RAc,

Thanks for the information provided. I understood what you have said. But, in the uc/OS III reference manual , it is mentioned that uc/OS II doesn’t supports run time configuration but uc/OS III supports run time configuration. Then, I wished to check it in the case of freeRTOS.

Thank you very much @RAc and @hs2

could you provide a link to the document you refer to?

Yes, I tried to upload it that time itself. A message prompted when I have pasted the link, saying new users are not allowed to put the link here.

By searching with the key sentence: “uc/OS III reference manual”, we will get that document from the web address wwwDOTanalogDOTcom.

Thanking you.

you mean the docs in Appendix B in the book? Yes, that seems to be exactly the counterpart to freertsconfig.h. Note that this only defines the OSs parameters, not (as I suspected earlier) the real tasks/ISRs etc.


Yes FreeRTOS is run-time configurable. It is also very configurable at compile-time.


uC/OS and FreeRTOS are different real time operating systems with similar characteristics. They both have a great number of configuration options for optimizing their memory footprint at compile time and a large number of parameters to functions that result in run-time configuration.

It is beyond the scope of the forums to produce a document that attempts to align all the features of both operating systems and identify the source of the configuration for each feature. If you have specific questions about specific features it will be much easier to get a satisfactory response.

Right, thank you very much @RAc for the continuous response.

Thanking you.

Thank you very much @jjulich. I understood what you have said and I have noted the same.

Thanking you.