atomic patch not working for esp32

Hardware description: esp32
RTOS: FreeRTOS
Installation type: espidf, component
Version or commit hash: humble

Steps to reproduce the issue

Clone this repo in components folder, then as always:

idf.py set-target esp32
idf.py build

Actual behavior

build fails:

/home/raphael/.espressif/tools/xtensa-esp-elf/esp-13.2.0_20240530/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: esp-idf/newlib/libnewlib.a(stdatomic.c.obj): in function `__atomic_exchange_8':
/home/raphael/esp/v5.3/esp-idf/components/newlib/stdatomic.c:77: multiple definition of `__atomic_exchange_8'; /home/raphael/idf_components/micro_ros_espidf_component/libmicroros.a(librcutils-atomic_64bits.c.obj):atomic_64bits.c:(.text.__atomic_exchange_8+0x0): first defined here
/home/raphael/.espressif/tools/xtensa-esp-elf/esp-13.2.0_20240530/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: esp-idf/newlib/libnewlib.a(stdatomic.c.obj): in function `__atomic_fetch_add_8':
/home/raphael/esp/v5.3/esp-idf/components/newlib/stdatomic.c:77: multiple definition of `__atomic_fetch_add_8'; /home/raphael/idf_components/micro_ros_espidf_component/libmicroros.a(librcutils-atomic_64bits.c.obj):atomic_64bits.c:(.text.__atomic_fetch_add_8+0x0): first defined here
/home/raphael/.espressif/tools/xtensa-esp-elf/esp-13.2.0_20240530/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: esp-idf/newlib/libnewlib.a(stdatomic.c.obj): in function `__atomic_load_8':
/home/raphael/esp/v5.3/esp-idf/components/newlib/stdatomic.c:77: multiple definition of `__atomic_load_8'; /home/raphael/idf_components/micro_ros_espidf_component/libmicroros.a(librcutils-atomic_64bits.c.obj):atomic_64bits.c:(.text.__atomic_load_8+0x0): first defined here
/home/raphael/.espressif/tools/xtensa-esp-elf/esp-13.2.0_20240530/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: esp-idf/newlib/libnewlib.a(stdatomic.c.obj): in function `__atomic_store_8':
/home/raphael/esp/v5.3/esp-idf/components/newlib/stdatomic.c:77: multiple definition of `__atomic_store_8'; /home/raphael/idf_components/micro_ros_espidf_component/libmicroros.a(librcutils-atomic_64bits.c.obj):atomic_64bits.c:(.text.__atomic_store_8+0x0): first defined here
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
ninja failed with exit code 1, output of the command is in the

Additional information

By modifying the file libmicroros.mk i was able to make it work:
in line 110 i added esp32 as target too. So the full line looks like this then:
ifeq ($(IDF_TARGET),$(filter $(IDF_TARGET), esp32 esp32s2 esp32c3))
However, i`m not experienced enough to know whether this has any side effects and is a valid change.

I met the same error:( with my ESP32-S3. libnewlib.a form ESP-IDF & newlib and libmicroros.a form micro-ROS
is conficting, which means my ESPIDF-V5.4 has no idea on __atomic_exchange_8、__atomic_fetch_add_8

Hi, I'm experiencing the same issue with micro-ros on ESP32 S3 using ESP-IDF V5.3.1.
esp-idf/components/newlib/stdatomic.c:77: multiple definition of __atomic_fetch_add_8';

Has this issue been patched or solved ?

EDIT: however, adding esp32s3 to the patch_atomic section in libmicroros.mk worked for me:
feq ($(IDF_TARGET),$(filter $(IDF_TARGET),esp32s3 esp32s2 esp32c3 esp32c6))

ESP32 S3 is quite popular, it would be great if someone could add it to patch_atomic.

@Roboprotos

@Roboprotos
My issue was just as same as yours. My ESPIDF told me those __atomic__functions were defined for twice. I had tried plenty of methods but none works.

I tried to give a clear order in my Cmakelists to make sure those functions from ESPIDF should be "neglected" while only the ones from Micro-ROS are on thery duty but this DIDN'T WORK.

Then I tried to delete these functions in /esp-idf/newlib/stdatomic.c. BUT the error occurred again.

At last I had to use a complete OS from the shop which I bought my ESP32-S3 from. This time it works with no error.

HOPE you could find the solutions !

@Roboprotos

@Roboprotos
You can try previous versions of ESPIDF. The owner of the shop tells me to use ROS2-humble, Micro-ROS-humble and ESPIDF-V5.1.2.

MAYBE this works !

@Care-Again

@Care-Again Thank you for your feedback. I wrote the solution I found at the end of my previous comment. It works for me using ESP-IDF v5.3.1, ESP32 S3 and jazzy branch of micro-ros espidf component.

@Care-Again

@Care-Again For future reference, the combination of ROS2-humble, MicroROS-humble, and ESPIDF-v5.1.2 worked for me!

I am encountering the exact same issue with ESP-IDF v5.5 (Master) targeting the ESP32-S3.

Context:
I cannot downgrade to the stable version (v5.3) because my project strictly requires specific DMA features for the ESP32-S3 that are currently only available in v5.5.

Workaround:
Since GCC 14 (bundled with IDF v5.5) now includes built-in atomic implementations that conflict with rcutils, I managed to fix the build by patching the CMakeLists.txt of the component to force the linker to accept multiple definitions.

In components/micro_ros/CMakeLists.txt, append the interface link option at the end:

add_dependencies(${COMPONENT_LIB} libmicroros-prebuilt)
target_link_libraries(${COMPONENT_LIB} INTERFACE libmicroros-prebuilt)

# FIX: Allow multiple definitions to handle GCC 14 / micro-ROS atomic conflict
target_link_libraries(${COMPONENT_LIB} INTERFACE "-Wl,--allow-multiple-definition")

After applying this change and running a full clean (rm -rf build / idf.py build), the project compiles successfully.

Fix rolling builds

I ran a test: based on the humble branch of this repository, I tried building the examples/int32_publisher using different versions of ESP-IDF and for different target chips. Here are the test results:

version	ESP32	ESP32S3	ESP32C3
5.2	T,✅	T,✅	U,✅
5.3	T,❌	T,❌	U,✅
5.4	T,❌	T,❌	U,✅
5.5	U,✅	U,✅	U,✅

T: libmicroros.a contains atomic operations.
U: libmicroros.a does not contain atomic operations.
❌: Build failed due to duplicate definition of atomic operations.
✅: Build succeeded.

ESP-IDF 6.0: Build failed, possibly because ESP-IDF has been using picolibc by default since 6.0.

On ESP-IDF 5.2, libmicroros.a includes atomic operations but does not cause a build failure. This appears to be because atomic operations are not used internally by ESP-IDF, so its built-in atomic operations are not actually linked. On version 5.3, however, ESP-IDF has introduced some atomic operations internally. See:

This then leads to a build failure.

One more thing: I tried adding atomic operations manually in ESP-IDF version 5.2 and successfully triggered a duplicate definition error for atomic operations.

The patch_atomic mechanism in the libmicroros.mk comes from #18. It was introduced to address the issue that ESP-IDF only provided partial atomic operations. From version 5.2 onward, it seems that ESP-IDF provides complete atomic operations. Therefore, perhaps we can simply disable the micro-ROS 64-bit atomic extension and remove patch_atomic? I'll give it a try later.

micro_ros_espidf_component/colcon.meta

Line 20 in b2af7b2

"-DRCUTILS_NO_64_ATOMIC=ON",

Fix rolling builds

Since the atomic patch has been removed, this issue can be closed.

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atomic patch not working for esp32 #251

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atomic patch not working for esp32 #251

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Care-Again commented on Jun 27, 2025

Roboprotos commented on Jun 28, 2025

Care-Again commented on Jun 29, 2025

Care-Again commented on Jun 29, 2025

Roboprotos commented on Jun 29, 2025

kmarques-24 commented on Oct 19, 2025

JoseGomesJr commented on Jan 23, 2026

Narukara commented on Apr 13, 2026

Narukara commented on Apr 13, 2026

Narukara commented on Apr 13, 2026

Narukara commented on May 27, 2026

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