Understanding the Error
- The error "undefined reference to operator new(unsigned int)" occurs when the linker cannot find the definition for the global `operator new` function.
- This is common in environments where C++ is partially supported, such as specific firmware or microcontroller compilers, which might not fully implement dynamic memory allocation features by default.
Check for Compiler and Linker Support
- Ensure that your toolchain supports C++ features, including dynamic memory allocations. Some embedded compilers might exclude dynamic allocations for size or safety considerations.
- Consult your compiler manual or documentation for enabling those features if they are disabled by default.
Implement a Custom operator new
- If dynamic memory allocation is required and the default implementation is unavailable, you can provide your own version of `operator new`. Here's an example:
void* operator new(size_t size) {
return malloc(size); // Use your own memory manager if needed
}
void operator delete(void* pointer) noexcept {
free(pointer);
}
Ensure to include `#include ` or equivalent headers for `malloc` and `free`.
Using `malloc` and `free` can be a temporary workaround, but it might not be ideal for all embedded environments.
Check Linking Options
- Ensure that the proper runtime libraries are linked with your project. Sometimes these errors occur because the standard C++ library is not linked. Check your linker options for flags like `-lstdc++` or equivalent options for your toolchain.
- Inspect the build configuration files or makefiles for any disparities in linking standard libraries.
Analyze your Code
- Review the portions of your code that invoke `new`, and consider if the use of dynamic memory is essential, especially in constrained environments like firmware development.
- If possible, refactor code to use statically allocated memory or stack-based allocations to prevent the need for `operator new`.
Alternative Memory Management Strategies
- Given the constraints in embedded systems, consider using custom memory pools or allocators that suit the memory management demands of your specific application.
- Designing a memory pool that fits your firmware architecture can increase reliability and performance.
Testing and Validation
- After making changes, ensure that all memory allocations and deallocations are tested under realistic conditions to ensure stability and performance are within acceptable limits.
- Run static code analyzers or tools available in your environment to verify that the new implementations meet safety and performance requirements.
