# [−][src]Function core::intrinsics::count_code_region

    #[lang = "count_code_region"]pub unsafe extern "rust-intrinsic" fn count_code_region(index: 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 placeholder for injecting code coverage counters when the "instrument-coverage" option is enabled. The placeholder is replaced with `llvm.instrprof.increment` during code generation.