Module Base.Printf

Functions for formatted output.

val ifprintf : 'a ‑> ('r, 'a, 'c, unit) Pervasives.format4 ‑> 'r

val sprintf : ('r, unit, string) Pervasives.format ‑> 'r

val bprintf : Caml.Buffer.t ‑> ('r, Caml.Buffer.t, unit) Pervasives.format ‑> 'r

val ksprintf : (string ‑> 'a) ‑> ('r, unit, string, 'a) Pervasives.format4 ‑> 'r

val kbprintf : (Caml.Buffer.t ‑> 'a) ‑> Caml.Buffer.t ‑> ('r, Caml.Buffer.t, unit, 'a) Pervasives.format4 ‑> 'r

Formatting error and exit functions

These functions have a polymorphic return type, since they do not return. Naively, this doesn't mix well with variadic functions: if you define, say,

      let f fmt = ksprintf (fun s -> failwith s) fmt

then you find that f "%d" : int -> 'a, as you'd expect, and f "%d" 7 : 'a. The problem with this is that 'a unifies with (say) int -> 'b, so f "%d" 7 4 is not a type error -- the 4 is simply ignored.

To mitigate this problem, these functions all take a final unit parameter. These rarely arise as formatting positional parameters (they can do with e.g. "%a", but not in a useful way) so they serve as an effective signpost for "end of formatting arguments".

val failwithf : ('r, unit, string, unit ‑> _) Pervasives.format4 ‑> 'r

Raises Failure.

val invalid_argf : ('r, unit, string, unit ‑> _) Pervasives.format4 ‑> 'r

Raises Invalid_arg.