Clangd throw an error when passing a pointer to an atomic var to atomic_init()

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Summary

The issue at hand is that clangd throws an error when passing a pointer to an atomic variable to atomic_init(), while no error is thrown when passing a pointer to a non-atomic variable. This error occurs despite the code compiling without issues.

Root Cause

The root cause of this error is due to the incompatible pointer types being passed to atomic_init(). The function expects a pointer of type _Atomic(int), but a pointer of type int is being passed instead. This is because the atomic_int type is defined as _Atomic(int), which is not the same as int.

Why This Happens in Real Systems

This issue can occur in real systems when:

  • Using atomic variables with atomic_init()
  • Passing pointers to atomic variables to functions that expect non-atomic pointers
  • Not properly including the <stdatomic.h> header file
  • Using clangd with CLion for code analysis

Real-World Impact

The real-world impact of this issue includes:

  • Compilation errors due to incompatible pointer types
  • Runtime errors if the code is compiled without proper warnings
  • Difficulty in debugging due to the lack of clear error messages
  • Performance issues if the code is not properly optimized for atomic operations

Example or Code

#include 

int main() {
    atomic_int foo;
    atomic_init(&foo, 0); // This will throw an error in clangd

    int bar;
    atomic_init(&bar, 0); // This will not throw an error in clangd

    return 0;
}

How Senior Engineers Fix It

Senior engineers can fix this issue by:

  • Properly including the <stdatomic.h> header file
  • Using the correct pointer type when passing to atomic_init()
  • Casting the pointer to the correct type if necessary
  • Using atomic_int instead of int for atomic variables

Why Juniors Miss It

Juniors may miss this issue due to:

  • Lack of understanding of atomic variables and their usage
  • Not properly including the <stdatomic.h> header file
  • Not paying attention to clangd warnings and errors
  • Not having experience with CLion and its code analysis features
  • Not understanding the difference between _Atomic(int) and int types