Function lua_checkstack 

pub unsafe extern "C-unwind" fn lua_checkstack(
    L: *mut lua_State,
    sz: c_int,
) -> c_int

Attempts to make space on the stack for at least n more values.

This function will attempt to make space on the stack for at least sz more values. If the stack is already large enough, this function does nothing. If the stack is not large enough, it will attempt to grow the stack to accommodate the new values.

If the stack cannot be grown, this function will return 0, otherwise it will return 1.