# [−][src]Function std::intrinsics::coverage_counter_add

    #[lang = "coverage_counter_add"]pub unsafe extern "rust-intrinsic" fn coverage_counter_add(
        index: u32,
        left_index: u32,
        right_index: u32,
        file_name: &'static str,
        start_line: u32,
        start_col: u32,
        end_line: u32,
        end_col: u32
    )

🔬 This is a nightly-only experimental API. (`core_intrinsics`)

intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library

Internal marker for code coverage expressions, injected into the MIR when the "instrument-coverage" option is enabled. This intrinsic is not converted into a backend intrinsic call, but its arguments are extracted during the production of a "coverage map", which is injected into the generated code, as additional data. This marker identifies a code region and two other counters or counter expressions whose sum is the number of times the code region was executed.