]> Basile STARYNKEVITCH <basile@starynkevitch.net> writes: > Adrien wrote: >> Hi, >> >> I am currently trying to bind a C function that takes variables >> arguments, like foo(int a, ...). I can't find how to make a C stub for >> that function. > > I am assuming that the a is the number of actual arguments, so you call > foo(3, x, y, z) > foo(5, t, t+1, t+3, 0, 4) > foo(0) > >> >> Any other idea? Hint^WPointer? (sorry for the bad joke ;-) ) > > First, you could suppose that the a has a reasonable limit, say 100. > > Then you could generate the glue code for each value of the argument > a. I mean generate ocaml code like > > external f0: void -> uit = "f_0" > external f1: int -> unit = "f_1" > external f2: int -> int -> unit = "f_2" > external f3: int -> int -> int -> unit = "f_3" > > let f a = match Array.length a with > 0 -> f0 () > | 1 -> f1 a.[0] > | 2 -> f2 a.[0] a.[1] > | 3 -> f3 a.[0] a.[1] a.[2] > .... > | _ -> failwith "too many components for f" > > and generate C code for each of f_0 f_1 ... > > and call f with an array ... > > The specialized code generator is reasonably written in Ocaml > > There are more crazy variants, including > > try Ocaml varargs like Pierre Weis did in printf.ml. For plain mortals > like me this is white magic. > > Assuming a Linux system, you could lazily generate the glue code and > invoke dynamic linker on it. So the general case would be to call the > code generator. > > Time to go to bed. I am saying lot of non-sense. > > Bye! Since ocaml functions with more than 5 args use an array you only do that in ocaml for a few arguments and then you need to do this in C. So do it in C for all. The stub takes an array and then switches on the lentgh to call the real function. Unfortunately you can not convert an array or list into a va_list. You need to specifically catch each length and call foo(4, a[0], a[1], a[2], a[3]) for each length. MfG Goswin