# Extra Clang Tools 21.1.6 documentation

## clang-tidy - misc-use-internal-linkage

# misc-use-internal-linkage

Detects variables and functions that can be marked as static or moved into an anonymous namespace to enforce internal linkage.

Static functions and variables are scoped to a single file. Marking functions and variables as static helps to better remove dead code. In addition, it gives the compiler more information and allows for more aggressive optimizations.

Example:

    int v1; // can be marked as static

    void fn1() {} // can be marked as static

    namespace {
      // already in anonymous namespace
      int v2;
      void fn2();
    }
    // already declared as extern
    extern int v2;

    void fn3(); // without function body in all declaration, maybe external linkage
    void fn3();

    // export declarations
    export void fn4() {}
    export namespace t { void fn5() {} }
    export int v2;

## Options

FixMode

  Selects what kind of a fix the check should provide. The default is UseStatic.

  `None`

    Don’t fix automatically.

  `UseStatic`

    Add `static` for internal linkage variable and function.