# The C compiler identification is unknown?

**URL:** <https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502>\
**Category:** Jetson Nano\
**Tags:** opencv\
**Created:** [June 22, 2022, 9:21am UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502 "2022-06-22T09:21:57Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![nantideh4](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@nantideh4](https://forums.developer.nvidia.com/u/nantideh4)\
**Post date:** [June 22, 2022, 9:21am UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/1 "2022-06-22T09:21:57Z")

</div>

I’m going to activate the cuda compiler in opencv but when doing a make build I get an error like this “the c compiler identification is unknown”

---

<div class="post-metadata">

**Author:** ![kayccc](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/kayccc/32/14043_2.png) [@kayccc](https://forums.developer.nvidia.com/u/kayccc)\
**Post date:** [June 22, 2022, 11:09pm UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/2 "2022-06-22T23:09:37Z")

</div>

You want to manually enable CUDA filters and build OpenCV, right?  
A user has shared a script:  
[GitHub - mdegans/nano\_build\_opencv: Build OpenCV on Nvidia Jetson Nano](https://github.com/mdegans/nano_build_opencv)

Please give it a try.

---

<div class="post-metadata">

**Author:** ![nantideh4](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@nantideh4](https://forums.developer.nvidia.com/u/nantideh4)\
**Post date:** [June 23, 2022, 2:44am UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/3 "2022-06-23T02:44:45Z")

</div>

> [@nantideh4](#):
>
> the c compiler identification is unknown”

I got the error “the c compiler identification is unknown”

---

<div class="post-metadata">

**Author:** ![nantideh4](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@nantideh4](https://forums.developer.nvidia.com/u/nantideh4)\
**Post date:** [June 23, 2022, 3:23am UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/5 "2022-06-23T03:23:31Z")

</div>

![Screenshot from 2022-06-23 11-18-05](https://global.discourse-cdn.com/nvidia/original/3X/9/0/90fa84313ec3d7351898abca48b229ff0b43ede2.jpeg)

---

<div class="post-metadata">

**Author:** ![DaneLLL](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/danelll/32/14043_2.png) [@DaneLLL](https://forums.developer.nvidia.com/u/DaneLLL)\
**Post date:** [June 23, 2022, 3:35am UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/6 "2022-06-23T03:35:35Z")

</div>

Hi,  
We have tried the [script](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/2) and it works fine. If you still hit issue, please re-install system image through SDKManager and try again.

---

<div class="post-metadata">

**Author:** ![linuxdev](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/linuxdev/32/10243_2.png) [@linuxdev](https://forums.developer.nvidia.com/u/linuxdev)\
**Post date:** [June 23, 2022, 5:53pm UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/7 "2022-06-23T17:53:27Z")

</div>

I saw some non-Jetson related issues suggesting to post the output of:  
`CMakefiles/CMakeError.log`

Another post suggested that in some cases the files in need of access required root privilege (`sudo`), but the `CMakeError.log` would probably clarify that. The key seems to be that the compiler must be found, and a simple test program must compile. The error log might give details on why this failed.

---

<div class="post-metadata">

**Author:** ![system](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/system/32/68080_2.png) [@system](https://forums.developer.nvidia.com/u/system)\
**Post date:** [July 13, 2022, 7:30am UTC](https://forums.developer.nvidia.com/t/the-c-compiler-identification-is-unknown/218502/9 "2022-07-13T07:30:09Z")

</div>

Closed on July 13, 2022, 7:30am UTC

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.