You specifiy variadic parameters as :varargs, and when you call the
function, you need to explicitly specify the type of the parameters.
e.g.
# this says printf takes a string parameter, followed by a variable
number of parameters
  attach_function :printf, [ :string, :varargs ], :int

# You don't need to specify the type of any fixed params, since it is part of
# the function signature, but you do need to for each varargs parameter

LibC.printf("Hello, %s", :string, "World")


2009/10/21 Gimi <liang.gimi@gmail.com>:

>
> Hi, it's me again : )
>
> I just wanna ask one more question, how to deal with the va_list
> parameter? Like the vprintf method, how to attach and call it?
>
> With many thanks!
> Gimi
>
> On Oct 20, 10:10 am, Gimi <liang.g...@gmail.com> wrote:

>> Hi all,
>>
>> I'm new to FFI, and I have a basic question about types. Assume there
>> is some C code like this:
>> # -- C code begin --
>> #if some situation
>> typedef sometype unsignedint
>> #else
>> typedef sometype int
>> #endif
>>
>> void some_function(sometype);
>> #-- C code end --
>>
>> So I mean when the types of parameters of a function are different in
>> different situations, how do I write the Ruby code?
>>
>> Any help will be greatly appreciated.
>>
>> Regards,