use cvt::cvt; use winapi::um::{profileapi::QueryPerformanceFrequency, winnt::LARGE_INTEGER}; pub fn perf_counter_frequency() -> std::io::Result { unsafe { let mut frequency: LARGE_INTEGER = std::mem::zeroed(); cvt(QueryPerformanceFrequency(&mut frequency))?; Ok(*frequency.QuadPart() as u64) } }