OpenCV on M1 Macs: Conquering the ARM64 Error
Problem: If you're trying to use OpenCV in your C++ projects on a Macbook with an M1 chip (or other ARM-based Macs), you might encounter the frustrating "architecture arm64" error. This error means OpenCV isn't recognizing your computer's architecture correctly, preventing your project from building.
Scenario:
Let's assume you're working on a simple OpenCV project in C++ that displays an image:
#include <opencv2/opencv.hpp>
int main() {
cv::Mat image = cv::imread("path/to/image.jpg");
if (!image.empty()) {
cv::imshow("Image", image);
cv::waitKey(0);
}
return 0;
}
When you try to compile this code, you might see an error like:
Undefined symbols for architecture arm64:
"___clang_call_terminate", referenced from:
_Unwind_Resume in libopencv_core.a(core_c.cpp.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Analysis and Solution:
The core of the problem lies in OpenCV's binaries being compiled for the wrong architecture. OpenCV, by default, is built for x86-64 architecture, which is the standard for Intel-based Macs. However, Apple's M1 chips use ARM64 architecture.
Here's how to fix it:
-
Install Homebrew: If you don't have it already, install Homebrew, a package manager for macOS.
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)" -
Install OpenCV with Homebrew: Homebrew provides pre-compiled packages of OpenCV specifically for ARM64 architecture.
brew install opencv@4This command will download and install OpenCV version 4, optimized for your M1 Mac.
-
Update your C++ project:
-
Include headers: Make sure you're including the correct OpenCV headers in your project:
#include <opencv2/opencv.hpp> -
Link OpenCV libraries: If you're using a build system like CMake, ensure you're linking the OpenCV libraries correctly in your project.
-
Additional Tips:
- Check for conflicts: If you have other versions of OpenCV installed, ensure you're using the one installed by Homebrew.
- Use a virtual environment: Consider using a virtual environment (e.g., virtualenv or conda) to manage dependencies and avoid conflicts.
- Update Homebrew: Regularly update Homebrew to ensure you have the latest versions of packages.
Resources:
- OpenCV Documentation: https://docs.opencv.org/
- Homebrew: https://brew.sh/
- Apple Developer Documentation: https://developer.apple.com/documentation/
Conclusion:
By installing OpenCV using Homebrew, you can seamlessly utilize OpenCV's powerful image processing capabilities on your Apple M1 Mac. Remember to double-check your project settings and include the correct OpenCV libraries to avoid any compatibility issues. Happy coding!
