I get linking errors when I use atomic functions in code. How could I solve it?

Hello, could you provide a full source example, as well as the command line(s) used.

Also FYI, the latest version of Arm Compiler for Embedded is 6.22.

See also:

https://developer.arm.com/documentation/101754/0618/Supporting-Information-Appendix/Standard-C---Implementation-Definition/Atomic-operations-library

I don't use any special compiler or linker flags regarding the atomic library. I use it in code like this:

header file:

#include <atomic>

namespace some_namespace
{
class SomeClass
{
public:
    SomeClass(std::atomic_flag* ExclusiveOperation = nullptr)
    : exclusiveOperation(ExclusiveOperation)
    {}

    void someFunction(void);
private:
    void anotherFunction(void);
    std::atomic_flag* const exclusiveOperation{nullptr};
};
}

cpp file that implements class functions:

#include "header_file.hpp"

namespace some_namespace
{
void SomeClass::someFunction(void)
{
    if(exclusiveOperation != nullptr && exclusiveOperation->test_and_set())
    {}
}

void SomeClass::anotherFunction(void)
{
    if(exclusiveOperation != nullptr)

    {

        exclusiveOperation->clear();

    }

}

cpp file where class instance is created:

#include "header_file.hpp"

std::atomic_flag exclusiveOperation = ATOMIC_FLAG_INIT;
SomeClass someClassInstance(&exclusiveOperation);

maybe it is related to this issue: github.com/.../73361

Hi Pavol, sorry for slow reply, I had to do some investigation.

The libatomic library is not provided, hence the link time errors.

Can you build with the compiler option -ffreestanding, to enable the compiler to generate appropriate code without relying on such a library call? I'm not sure if this is available with 6.18 of the compiler, it is only documented for 6.21 or later. The current compiler version is 6.22.

https://developer.arm.com/documentation/101754/0622/armclang-Reference/armclang-Command-line-Options/-ffreestanding

You can download the latest compiler version from the below.

https://developer.arm.com/documentation/ka005198