clock_gettime() via LuaJIT + FFI

clock_gettime

local ffi = require("ffi")

ffi.cdef[[
    typedef long time_t;
    typedef int clockid_t;

    typedef struct timespec {
            time_t   tv_sec;        /* seconds */
            long     tv_nsec;       /* nanoseconds */
    } nanotime;
    int clock_gettime(clockid_t clk_id, struct timespec *tp);
]]

function clock_gettime()
    local pnano = assert(ffi.new("nanotime[?]", 1))

    -- CLOCK_REALTIME -> 0
    ffi.C.clock_gettime(0, pnano)
    return pnano[0]
end

local nano = clock_gettime()
print(nano.tv_sec)
print(nano.tv_nsec)