Function luaL_findtable 

#[unsafe(no_mangle)]
pub unsafe fn luaL_findtable(
    l: *mut lua_State,
    idx: c_int,
    fname: *const c_char,
    szhint: c_int,
) -> *const c_char

const char* luaL_findtable(lua_State* L, int idx, const char* fname, int szhint)

C++ source: VM/src/laux.cpp:330