module Syscall_result

: sig

Representation of Unix system call results

Almost no Unix system call returns a negative integer in case of success.

We can use this to encode the result of a system call as either a positive integer value or -errno. This allows us to avoid exceptions for dealing with errors such as EAGAIN. Indeed, in some context we issue a system call in a tight loop that will often fail with EAGAIN and using exceptions to return it is costly.

type 'a t = private int

There is no with sexp_of on purpose as it could only print the 'a value as an integer. Use <:sexp_of< Int.t >> or <:sexp_of< Unit.t >>.

module type S = Syscall_result_intf.S with type 'a syscall_result := 'a t

module type Arg = Syscall_result_intf.Arg

module Make : functor (M : Arg) -> functor () -> S with type ok_value := M.t

module Int : S with type ok_value := int

module Unit : S with type ok_value := unit

val create_error : Unix_error.t -> _ t

val unit : Unit.t

val ignore_ok_value : _ t -> Unit.t

Keep only the error.

end