TFLM / C++ library issues

Murphy, Lauren

Hi Bharath,

You may want to consider modeling your prj.conf off of the TensorFlow Lite Micro hello_world sample as well ( You will probably also need to copy the CMakeLists.txt from that sample if you use any local static initialization - see comment below.

cmake_minimum_required(VERSION 3.20.0)


# These samples use local static initialization. Since Zephyr doesn't support the
# C++ ABI for thread-safe initialization of local statics and the constructors don't
# appear to require thread safety, we turn it off in the C++ compiler.
set(NO_THREADSAFE_STATICS $<TARGET_PROPERTY:compiler-cpp,no_threadsafe_statics>)

file(GLOB app_sources src/*)
target_sources(app PRIVATE ${app_sources})

If you do happen to need thread-safe local static initialization... well, you can file a feature request asking for ABI support, but we only support a limited subset of C++ ( so I'm not sure if it'll be accepted.

Right now, there are two approaches to using TFLM with Zephyr that you can follow:
1. Use the TFLM build system with a static commit of Zephyr (model your project after this example:
2. Use the Zephyr build system with a static copy of the TFLM 2.5.0 library as a Zephyr "module": (model your project after this example:

The Google maintainers recommend (1), since they helped Antmicro to develop that sample repository. (1) also lets you use a more recent version of TFLM (October 2021, instead of April 2021 / 2.5.0 for the module) and gives you more control over TFLM's configuration but takes away your control of Zephyr's. I introduced (2) last year so that users could directly use the Zephyr build / configuration system, but that similarly means you can't configure TFLM directly.

If you do decide to use the module, tag me @laurenmurphyx64 if you file GitHub issues. I'm not a TFLM jock, but I introduced the module and the samples in the Zephyr tree. I did the verification on the Renode simulator for litex_vexriscv, so it's possible you'll encounter some weirdness on the actual hardware. Also, if you find yourself configuring TFLM in certain ways you think most people would benefit from, let me know and I may be able to introduce it as a Kconfig option for the module.

Lauren Murphy

-----Original Message-----
From: users@... <users@...> On Behalf Of Guy Morand
Sent: Thursday, February 17, 2022 12:02 AM
To: users@...
Subject: Re: [Zephyr-users] C++ library issues

Hi Baharath,

I also struggle a little to get cpp running, I needed the following configuration in my project to make it work:



On 16/02/2022 16:42, Bharath V wrote:
Dear Team

I am currently working on implementing Tensorflow lite on RISC-V
vexRISC-V) using Zephyr RTOS. I have successfully installed Zephyr
RTOS (with SDK) and am able to run the blinky program. I am facing an
issue with the C++ libraries while using tensorflow lite. I not able
to include cstdarg library in tensorflow lite libraries or the main.c
program. The exact issue is mentioned below.


/home/bharath/zephyrproject/zephyr/hello_world/src/main.c:8:10: fatal
error: cstdarg: No such file or directory
    8 | #include <cstdarg>
      |          ^~~~~~~~~
compilation terminated.


I am using the west utility to build the code. Kindly requesting for

Thanks and regards
Bharath V
bytes at work
Technoparkstrasse 7
CH-8406 Winterthur

phone: +41 52 213 79 79