# CheckLinkerFlag

New in version 3.18.

Check whether the compiler supports a given link flag.

`check_linker_flag`

      check_linker_flag(<lang> <flag> <var>)

Check that the link `<flag>` is accepted by the `<lang>` compiler without a diagnostic. Stores the result in an internal cache entry named `<var>`.

This command temporarily sets the `CMAKE_REQUIRED_LINK_OPTIONS` variable and calls the `check_source_compiles()` command from the `CheckSourceCompiles` module. See that module’s documentation for a listing of variables that can otherwise modify the build.

The underlying implementation relies on the `LINK_OPTIONS` property to check the specified flag. The `LINKER:` prefix, as described in the `target_link_options()` command, can be used as well.

A positive result from this check indicates only that the compiler did not issue a diagnostic message when given the link flag. Whether the flag has any effect or even a specific one is beyond the scope of this module.

Note

Since the `try_compile()` command forwards flags from variables like `CMAKE_<LANG>_FLAGS`, unknown flags in such variables may cause a false negative for this check.